REGULATORY GUIDE 1.208

The US Nuclear Regulatory Com m ission (NRC) issues regulatory guides to describe and make available to the public methods that the NRC staff

considers acceptable for use in im plem enting specific parts of the agencyrsquos regulations techniques that the staff uses in evaluating specific problem s or

postulated accidents and data that the staff need in reviewing applications for perm its and licenses Regulatory guides are not substitutes for

regulations and com pliance with them is not required Methods and solutions that differ from those set forth in regulatory guides will be deem ed

acceptable if they provide a basis for the findings required for the issuance or continuance of a perm it or license by the Com m ission

This guide was issued after consideration of com m ents received from the public The NRC staff encourages and welcomes comm ents and suggestions

in connection with im provem ents to published regulatory guides as well as item s for inclusion in regulatory guides that are currently being developed

The NRC staff will revise existing guides as appropriate to accom m odate com m ents and to reflect new inform ation or experience W ritten com m ents

m ay be submitted to the Rules and Directives Branch Office of Adm inistration US Nuclear Regulatory Com m ission W ashington DC 20555-0001

Regulatory guides are issued in 10 broad divisions 1 Power Reactors 2 Research and Test Reactors 3 Fuels and Materials Facilities 4

Environm ental and Siting 5 Materia ls and Plant Protection 6 Products 7 Transportation 8 Occupational Health 9 Antitrust and Financial Review

and 10 General

Requests for single copies of draft or active regulatory guides (which m ay be reproduced) should be made to the US Nuclear Regulatory Com m ission

W ashington DC 20555 Attention Reproduction and Distribution Services Section or by fax to (301) 415-2289 or by email to D istribution nrcgov

E lectronic copies of this guide and other recently issued guides are available through the NRCrsquos public W eb site under the Regulatory Guides document

collection of the NRCrsquos Electronic Reading Room at httpwwwnrcgovreading-rm doc-collections and through the NRCrsquos Agencywide Docum ents

Access and Managem ent System (ADAMS) at httpwwwnrcgovreading-rm adam shtm l under Accession No ML070310619

US NUCLEAR REGULATORY COMMISSION March 2007

REGULATORY GUIDEOFFICE OF NUCLEAR REGULATORY RESEARCH

REGULATORY GUIDE 1208(Draft was issued as DG-1146 dated October 2006)

A PERFORMANCE-BASED APPROACH TO DEFINE

THE SITE-SPECIFIC EARTHQUAKE GROUND MOTION

A INTRODUCTION

This regulatory guide provides an alternative for use in satisfying the requirements set forth inSection 10023ldquoGeologic and Seismic Siting Criteriardquo of Title 10 Part 100 of the Code of FederalRegulations (10 CFR Part 100) ldquoReactor Site Criteriardquo (Ref 1) The NRC staff incorporateddevelopments in ground motion estimation models updated models for earthquake sources methods fordetermining site response and new methods for defining a site-specific performance-based earthquakeground motion that satisfy the requirements of 10 CFR 10023 and lead to the establishment of the safeshutdown earthquake ground motion (SSE) The purpose of this regulatory guide is to provide guidanceon the development of the site-specific ground motion response spectrum (GMRS) The GMRSrepresents the first part of the development of the SSE for a site as a characterization of the regional andlocal seismic hazard The final SSE must satisfy both 10 CFR 10023 and Appendix S ldquoEarthquakeEngineering Criteria for Nuclear Power Plantsrdquo to 10 CFR Part 50 ldquoDomestic Licensing of Productionand Utilization Facilitiesrdquo (Ref 2)

In 10 CFR 10023 paragraph (c) ldquoGeological Seismological and Engineering Characteristicsrdquoand paragraph (d) ldquoGeologic and Seismic Siting Factorsrdquo require that the geological seismological andengineering characteristics of a site and its environs be investigated in sufficient scope and detail topermit an adequate evaluation of the proposed site provide sufficient information to support evaluationsperformed to arrive at estimates of the SSE and permit adequate engineering solutions to actual orpotential geologic and seismic effects at the proposed site Data on the vibratory ground motion tectonicand non-tectonic surface deformation earthquake recurrence rates fault geometry and slip rates sitefoundation material seismically induced floods and water waves and other siting factors and designconditions should be obtained by reviewing pertinent literature and carrying out field investigations

RG 1208 Page 2

10 CFR 10023 paragraph (d)(1) ldquoDetermination of the Safe Shutdown Earthquake GroundMotionrdquo requires that uncertainty inherent in estimates of the SSE be addressed through an appropriateanalysis such as a probabilistic seismic hazard analysis (PSHA)

In Appendix A ldquoGeneral Design Criteria for Nuclear Power Plantsrdquo to 10 CFR Part 50 GeneralDesign Criterion (GDC) 2 ldquoDesign Bases for Protection Against Natural Phenomenardquo requires in partthat nuclear power plant structures systems and components (SSCs) important to safety must bedesigned to withstand the effects of natural phenomena (such as earthquakes) without loss of capabilityto perform their safety functions Such SSCs must also be designed to accommodate the effects of andbe compatible with the environmental conditions associated with normal operation and postulatedaccidents

Appendix S to 10 CFR Part 50 specifies in part requirements for implementing GDC 2 withrespect to earthquakes Paragraph IV(a)(1)(i) of Appendix S to 10 CFR Part 50 requires that the SSEmust be characterized by free-field ground motion response spectra at the free ground surface In view ofthe limited data available on vibratory ground motions of strong earthquakes it will usually beappropriate that the design response spectra be smoothed spectra compatible with site characteristics Inaddition the horizontal motions in the free field at the foundation level of the structures consistent withthe SSE must be an appropriate response spectrum with a peak ground acceleration of at least 01g

The 10 CFR Part 50 licensing practice required applicants to acquire a construction permit (CP)and then apply for an operating license (OL) during construction Alternatively the requirements andprocedures applicable to the NRCrsquos issuance of early site permits (ESPs) and combined licenses (COLs)for nuclear power facilities are set forth in Subparts A and C of 10 CFR Part 52 ldquoLicenses Certificationsand Approvals for Nuclear Power Plantsrdquo (Ref 3) respectively

This regulatory guide has been developed to provide general guidance on methods acceptable tothe NRC staff for (1) conducting geological geophysical seismological and geotechnical investigations(2) identifying and characterizing seismic sources (3) conducting a probabilistic seismic hazardassessment (PSHA) (4) determining seismic wave transmission (soil amplification) characteristics of soiland rock sites and (5) determining a site-specific performance-based GMRS satisfying the requirementsof paragraphs (c) (d)(1) and (d)(2) of 10 CFR 10023 and leading to the establishment of an SSE tosatisfy the design requirements of Appendix S to 10 CFR Part 50 The steps necessary to develop thefinal SSE are described in Chapter 3 ldquoDesign of Structures Components Equipment and Systemsrdquo ofNUREG-0800 ldquoStandard Review Plan for the Review of Safety Analysis Reports for Nuclear PowerPlantsrdquo (Ref 4) Regulatory Position 54 of this guide provides a more detailed description of thedevelopment of the final SSE

This regulatory guide contains several appendices that address the objectives stated above Appendix A contains a list of definitions Appendix B contains a list of abbreviations and acronyms Appendix C discusses a procedure to characterize site geology seismology and geophysics Appendix Ddescribes the procedure to determine the controlling earthquakes Appendix E describes the procedurefor determining seismic wave transmission (soil amplification) characteristics of soil and rock sites Appendix F provides criteria for developing and evaluating modified ground motions used for soilresponse analyses

This regulatory guide may address information collections that are covered by the requirementsof 10 CFR Part 50 10 CFR Part 52 and 10 CFR Part 100 which the Office of Management and Budget(OMB) approved under OMB control numbers 3150-0011 3150-0151 and 3150-0093 respectively TheNRC may neither conduct nor sponsor and a person is not required to respond to an informationcollection request or requirement unless the requesting document displays a currently valid OMB controlnumber

The CEUS and WUS Time History databases are provided in NUREGCR-6728 (Ref 6)1

RG 1208 Page 3

B DISCUSSION

Background

Regulatory Guide 1165 (Ref 5) provides general guidance on procedures acceptable to the NRCstaff to satisfy the requirements of 10 CFR 10023 This regulatory guide provides alternative guidancethat incorporates developments in ground motion estimation models updated models for earthquakesources methods for determining site response and new methods for defining a site-specificperformance-based GMRS Therefore the NRC staff is providing this regulatory guide as an alternativeto Regulatory Guide 1165 (Ref 5) to satisfy in part the requirements of 10 CFR 10023 and AppendixS to 10 CFR Part 50

The general process to determine a site-specific performance-based GMRS includes thefollowing

(1) site- and region-specific geological seismological geophysical and geotechnical investigations(2) a probabilistic seismic hazard analysis (PSHA)(3) a site response analysis to incorporate the effects of local geology and topography(4) the selection of appropriate performance goals and methodology

Geological seismological and geophysical investigations are performed to develop an up-to-date site-specific earth science database that supports site characterization and a PSHA The results ofthese investigations will also be used to assess whether new data and their interpretation are consistentwith the information used in probabilistic seismic hazard studies previously accepted by the NRC

The PSHA is conducted with up-to-date interpretations of earthquake sources earthquakerecurrence and strong ground motion estimation The site seismic hazard characteristics are quantifiedby the seismic hazard curves from a PSHA and the uniform hazard response spectra (UHRS) that cover abroad range of natural frequencies The hazard curves are developed in part by identifying andcharacterizing each seismic source in terms of maximum magnitude magnitude recurrence relationshipand source geometry The rock-based ground motion at a site resulting from the combined effect of allsources can then be determined through the use of attenuation relationships

Seismic wave transmission (site amplification) procedures are necessary to obtain appropriateUHRS at the free-field ground surface if the shear wave velocity of the surficial material is less than thegeneric rock conditions appropriate for the rock-based attenuation relationships used in the PSHA Adatabase of earthquake time histories on rock for both the central and eastern United States (CEUS) andthe western United States (WUS) has been developed to determine the dynamic site response for the soilor rock site conditions1

The reference probability is computed as the median probability obtained from the distribution of median probabilities2

of exceeding the SSE at 29 sites in the CEUS The sites selected were intended to represent relatively recent (to thestudy) designs that used the Regulatory Guide 160 (Ref 8) design response spectrum or similar spectrum as theirdesign bases The use of the reference probability ensures an adequate level of conservatism in determining the SSEconsistent with recent licensing decisions

F P DThe P R and H criteria corresponding to Seismic Design Category (SDC) 5 in Reference 7 (which are equivalent to3

nuclear power plant requirements) are used

RG 1208 Page 4

A performance-based approach is described in Chapters 1 and 2 of ASCESEI Standard 43-05(Ref 7) instead of the reference probability approach described in Appendix B to Regulatory Guide

F1165 (Ref 5) The performance-based approach employs Target Performance Goal (P ) Probability2

P DRatio (R ) and Hazard Exceedance Probability (H ) criteria to ensure that nuclear power plants can3

withstand the effects of earthquakes with a desired performance the desired performance beingexpressed as the target value of 1 E-05 for the mean annual probability of exceedance (frequency) of theonset of significant inelastic deformation (FOSID) This approach targets a performance criteria forSSCs which is defined relative to the onset of inelastic deformation instead of relative to the occurrenceof failure of the SSC The mean annual probability of exceedance associated with this performancetarget was chosen based on this performance criterion

One of the objectives in developing the performance-based GMRS is to achieve approximatelyconsistent performance for SSCs across a range of seismic environments annual probabilities and

Fstructural frequencies The intent is to develop a site-specific GMRS that achieves the P that ensuresthat the performance of the SSCs related to safety and radiological protection is acceptable

Basis for Regulatory Positions

Site- and Region-Specific Investigations to Characterize Site Geology Seismology and Geophysics

The primary objective of geological seismological and geophysical investigations is to developan up-to-date site-specific earth science database that supports site characterization and a PSHA Theresults of these investigations will also be used to assess whether new data and their interpretation areconsistent with the most recent information used in probabilistic seismic hazard studies accepted by theNRC If the new data such as new seismic sources and new ground motion attenuation relationships areconsistent with the existing earth science database updating or modification of information used in thehazard analysis is not required It will be necessary to update seismic sources and ground motionattenuation relationships for sites where there is significant new information resulting from the siteinvestigations

Features Discovered During Construction

It should be demonstrated that deformation features discovered during construction (particularlyfaults potential soft zones or other features of engineering significance) do not have the potential tocompromise the safety of the plant Applying the combined licensing procedure to a site could result inissuing a license prior to the start of construction During the construction of nuclear power plantslicensed in the past previously unknown faults were often discovered in site excavations Beforeissuance of the OL it was necessary to demonstrate that faults exposed in the excavation posed no hazardto the facility Under the combined license procedure these kinds of features should be mapped andassessed as to their rupture and ground motion generating potential while the excavationsrsquo walls andbases are exposed and the NRC staff should be notified when excavations are open for inspection

RG 1208 Page 5

Probabilistic Seismic Hazard Analysis Methods

A PSHA has been identified in 10 CFR 10023 as a means to address the uncertainties in thedetermination of the SSE Furthermore the rule recognizes that the nature of uncertainty and theappropriate approach to account for uncertainties depend on the tectonic setting of the site and onproperly characterizing input parameters to the PSHA such as the seismic source characteristics therecurrence of earthquakes within a seismic source the maximum magnitude of earthquakes within aseismic source and engineering estimation of earthquake ground motion through attenuationrelationships

Every site is unique therefore requirements for analyses and investigations vary It is notpossible to provide procedures for addressing all situations In cases that are not specifically addressedin this regulatory guide prudent and sound engineering judgment should be exercised

Probabilistic procedures were developed specifically for nuclear power plant seismic hazardassessments in the CEUS also referred to as the Stable Continent Region (SCR) Experience has beengained by applying this methodology at nuclear facility sites both reactor and non-reactor sitesthroughout the United States The experience with these applications also served as the basis for theguidelines for conducting a PSHA in Reference 9 The guidelines detailed in Reference 9 should beincorporated into the PSHA process to the extent possible These procedures provide a structuredapproach for decision making with respect to site-specific investigations A PSHA provides a frameworkto address the uncertainties associated with the identification and characterization of seismic sources byincorporating multiple interpretations of seismological parameters A PSHA also provides a means forevaluation of the likelihood of SSE occurrence during the design lifetime of a given facility given therecurrence interval and recurrence pattern of earthquakes in pertinent seismic sources Within theframework of a probabilistic analysis uncertainties in the characterization of seismic sources and groundmotions are identified and incorporated in the procedure at each step of the process for estimating theGMRS The role of geological seismological and geophysical investigations is to develop geoscienceinformation about the site for use in the detailed design analysis of the facility as well as to ensure thatthe seismic hazard analysis is based on up-to-date information

Experience in performing seismic hazard evaluations in active plate-margin regions in the WUS(for example the San Gregorio-Hosgri fault zone and the Cascadia Subduction Zone) has also identifieduncertainties associated with the characterization of seismic sources (Refs 10ndash12) Sources ofuncertainty include fault geometry rupture segmentation rupture extent seismic-activity rate groundmotion and earthquake occurrence modeling As is the case for sites in the CEUS alternativehypotheses and parameters must be considered to account for these uncertainties

Uncertainties associated with the identification and characterization of seismic sources intectonic environments in both the CEUS and the WUS should be evaluated While the most recentcharacterization of any seismic source accepted by the NRC staff can be used as a starting point foranalysis of a new facility any new information related to a seismic source that impacts the hazardcalculations must be evaluated and incorporated into the PSHA as appropriate based on the technicalinformation available

RG 1208 Page 6

Central and Eastern United States

The CEUS is considered to be that part of the United States east of the Rocky Mountain front oreast of Longitude 105E West (Refs 13 14) A PSHA in the CEUS must account for credible alternativeseismic source models through the use of a decision tree with appropriate weighting factors that arebased on the most up-to-date information and relative confidence in alternative characterizations for eachseismic source Seismic sources identified and characterized by the Lawrence Livermore NationalLaboratory (LLNL) (Refs 13ndash15) and the Electric Power Research Institute (EPRI) (Refs 16 17) wereused for studies in the CEUS in the past In addition to the LLNL and EPRI resources the United StatesGeological Survey also maintains a large database of seismic sources for both the CEUS and the WUS The characterization of specific seismic sources found in these databases may still represent the latestinformation available at the time that a PSHA is to be undertaken However if more up-to-dateinformation is available it should be incorporated

In the CEUS characterization of seismic sources is more problematic than in active plate-marginregions because there is generally no clear association between seismicity and known tectonic structuresor near-surface geology In general the observed geologic structures are a result of response to tectonicforces that may have little or no correlation with current tectonic forces Therefore it is important toaccount for this uncertainty by the use of multiple alternative source models

The identification of seismic sources and reasonable alternatives in the CEUS considershypotheses currently advocated for the occurrence of earthquakes in the CEUS (eg the reactivation offavorably oriented zones of weakness or the local amplification and release of stresses concentratedaround a geologic structure) In tectonically active areas of the CEUS such as the New Madrid SeismicZone where geological seismological and geophysical evidence suggest the nature of the sources thatgenerate the earthquakes it may be more appropriate to characterize those seismic sources by usingprocedures similar to those normally applied in the WUS

Western United States

The WUS is considered to be that part of the United States that lies west of the Rocky Mountainfront or west of approximately 105E West Longitude In some regions of the WUS significant researchinto seismic sources is ongoing and the results of this research should be evaluated and addressed

The active plate-margin regions include for example coastal California Oregon Washingtonand Alaska For the active plate-margin regions where earthquakes can often be correlated with knownfaults that have experienced repeated movements at or near the ground surface during the Quaternarytectonic structures should be assessed for their earthquake and surface deformation potential In theseregions at least three types of sources may exist

(1) faults that are known to be at or near the surface(2) buried (blind) sources that may often be manifested as folds at the earthrsquos surface(3) subduction zone sources such as those in the Pacific Northwest and Alaska

The nature of surface faults can be evaluated by conventional surface and near-surfaceinvestigation techniques to assess orientation geometry sense of displacements length of ruptureQuaternary history etc Possibilities of multiple ruptures should be considered as appropriate

Buried (blind) faults are often associated with surficial deformation such as folding uplift orsubsidence The surface expression of blind faulting can be detected by mapping the uplifted or down-dropped geomorphological features or stratigraphy survey leveling and geodetic methods The nature ofthe structure at depth can often be evaluated by deep core borings and geophysical techniques

RG 1208 Page 7

Continental US subduction zones are located in the Pacific Northwest and Alaska Seismicsources associated with subduction zones are sources within the overriding plate on the interfacebetween the subducting and overriding lithospheric plates and in the interior of the downgoing oceanicslab The characterization of subduction zone seismic sources should consider the three-dimensionalgeometry of the subducting plate rupture segmentation of subduction zones geometry of historicalruptures constraints on the up-dip and down-dip extent of rupture and comparisons with othersubducting plates worldwide

The Basin and Range region of the WUS and to a lesser extent the Pacific Northwest and thecentral United States exhibit temporal clustering of earthquakes Temporal clustering is bestexemplified by the rupture histories within the Wasatch fault zone in Utah where several large lateHolocene coseismic faulting events occurred at relatively close intervals (for hundreds to thousands ofyears) that were preceded by long periods of quiescence that lasted thousands to tens of thousands ofyears Temporal clustering should be considered in these regions or wherever paleoseismic evidenceindicates that it has occurred

Ground motion attenuation relationships for the WUS are also continually being developed andrevised Significant effort has been undertaken by the Pacific Earthquake Engineering Research CenterrsquosLifelines program to develop Next Generation Attenuation (NGA) relationships for shallow crustalearthquakes in active tectonic regions based on the large database of earthquake recordings now availablefor this tectonic setting The suitability of the NGA relationships or other WUS relationships for aparticular site will be evaluated on a case-by-case basis

Lower-Bound Magnitude Cutoff

Current seismic hazard analysis methods generally utilize a lower-bound body wave magnitudecut-off value for earthquakes to be included in the PSHA This lower-bound magnitude cut-off level is aconservatively defined value based on research studies whose objective was to estimate the damagepotential of smaller earthquakes Reference 18 establishes an appropriate distribution of low-magnitudeearthquakes in the seismic hazard analysis through the use of the cumulative absolute velocity (CAV)model in place of a lower-bound magnitude cutoff

Several ground motion measures such as peak ground acceleration Arias intensity root meansquare acceleration and CAV were evaluated to determine the single ground motion measure that is bestcorrelated with the threshold of potential damage The CAV was determined to be the best parametercorrelating damage with the Modified Mercalli Intensity Scale and a CAV value of 016 g-sec was foundto be a conservative characterization of the threshold between damaging and non-damaging earthquakemotions for buildings of good design and construction An empirical model for estimating CAV in termsof magnitude peak ground acceleration (PGA) and duration is needed because the PSHA calculationdoes not use time histories directly

Spectral Frequency Range Considered in the Probabilistic Seismic Hazard Analyses

The frequency range considered in the PSHA should extend from a low frequency that can bereliably obtained from the current strong-motion data set from the WUS principally California to a high-frequency limit that permits the ratio of spectral acceleration to PGA to reach nearly 1 for hard rock siteconditions For the CEUS this high-frequency limit is approximately 100 Hz For soft rock conditionsthe ratio of spectral acceleration to PGA will reach 1 at about 40ndash50 Hz To obtain a smooth plot ofspectral response across the frequency range of interest the hazard assessment should be provided for aminimum of 30 frequencies approximately equally spaced on a logarithmic frequency axis between 100and 01 Hz

RG 1208 Page 8

Deaggregation of Mean Hazard

Deaggregation provides information useful for review of the PSHA and insight into the seismicsources that most impact the hazard at a particular site It can also be used to determine the controllingearthquakes (ie magnitudes and distances) which can be used to perform dynamic site responseanalyses

Analysis of multiple ground motion levels are used to obtain a more complete understanding ofthe earthquake characteristics (ie mean magnitudes and distances) that contribute to the high-frequency(5 and 10 Hz) and low-frequency (1 and 25 Hz) hazard than could be obtained from a single groundmotion level (eg 1 E-05yr)

Choice of Epsilon in Probabilistic Seismic Hazard Analyses

Epsilon the number of standard deviations included in defining the distribution of groundmotions for each magnitude and distance scenario can have a significant impact on the results of thePSHA Care should be taken in choosing a value for epsilon large enough such that natural aleatoryvariability in ground motions is adequately addressed A study conducted by EPRI and the USDepartment of Energy (DOE) (Ref 19) found no technical basis for truncating the ground motiondistribution at a specified number of standard deviations (epsilons) below that implied by the strength ofthe geologic materials Even though very large ground motions may have a low probability ofoccurrence when the hazard is calculated for low annual frequencies of exceedance low probabilityevents need to be considered

Site Response Analysis

For rock or soil sites where the free-field ground surface shear wave velocity is less than thegeneric rock conditions defined by the attenuation relationships used in the PSHA seismic wavetransmission (site amplification) procedures should be used to obtain appropriate UHRS at the free-fieldground surface Earthquake time histories and time-domain procedures are one method that may be usedto determine the dynamic site response for the soil or rock site conditions When using this methodenough earthquake time history records should be used to get consistent mean results Reference 6contains a database of recorded time histories on rock for both the CEUS and WUS that can be used asseed records for input time histories for analyses The records provided in Reference 6 should be usedconsistently with the recommendations for use in Reference 6 (eg the records were developed to beused as seed motions for spectral matching programs rather than to be used directly) The database isdivided into magnitude and distance bins with each bin having a minimum of 15 three-component (twohorizontal and one vertical) sets

RG 1208 Page 9

Performance-Based Method

A performance-based approach is described in Chapters 1 and 2 of ASCESEI Standard 43-05(Standard) (Ref 7) The Standard was developed to provide performance-based criteria for the seismicdesign of safety-related SSCs for use in nuclear facilities covering a broad range of facilities thatprocess store or handle radioactive materials The goal of the Standard is to present seismic designcriteria using a graded approach commensurate with the relative importance to safety and safeguardswhich will ensure that nuclear facilities can withstand the effects of earthquakes with desiredperformance The performance-based approach used for this regulatory guide is based on the premisethat the seismic demand and structural capacity evaluation criteria laid out by the NRCrsquos StandardReview Plan (SRP) (NUREG-0800) ensure sufficient conservatism to reasonably achieve both of thefollowing

(1) less than about a 1 probability of unacceptable performance for the site-specific responsespectrum ground motion

(2) less than about a 10 probability of unacceptable performance for a ground motion equal to150 of the site-specific response spectrum ground motion

FThe Standard for the most demanding seismic design category (SDC 5) recommends using a P

P D= 1 E-05 for the FOSID R = 10 and H = 1 E-04 for the minimum structural damage state which isdescribed as essentially elastic behavior Specifically essentially elastic behavior means that localizedinelasticity might occur at stress concentration points but the overall seismic response will be essentiallyelastic

The performance-based approach combines a conservative characterization of ground motionhazard with equipmentstructure performance (fragility characteristics) to establish risk-consistentGMRS rather than only hazard-consistent ground shaking as occurs using the hazard referenceprobability approach in Appendix B to Regulatory Guide 1165 (Ref 5) The performance target (themean annual probability of SSCs reaching the limit state of inelastic response) results from themodification of the UHRS at the free-field ground surface by a design factor to obtain the performance-based site-specific GMRS The design factor achieves a relatively consistent annual probability of plantcomponent failure across the range of plant locations and structural frequencies It does this byaccounting for the slope of the seismic hazard curve which changes with structural frequency and sitelocation The design factor ensures that the site-specific response spectrum is equal to or greater than themean 1 E-04 UHRS

The flow chart in Figure 1 depicts the procedures described in this regulatory guide

RG 1208 0

Geological Geophysical Seismological andGeotechnical Investigations

Regulatory Position 1 Appendix C

Seismic Sources Significant to theSite Seismic Hazard


Probabilistic Seismic Hazard Analysis(PSHA) Procedures

Regulatory Position 3


Regulatory Position 35 Appendix D

Seismic Wave Transmission(Soil Amplification) Characteristics of the Site

Regulatory Position 4 Appendices E amp F

Performance-Based Site-Specific EarthquakeGround Motion Procedure


Figure 1 Flow Diagram

RG 1208 Page 11

C REGULATORY POSITION

1 Geological Geophysical Seismological and Geotechnical Investigations

11 Comprehensive Site Area and Region Investigations

Comprehensive geological seismological geophysical and geotechnical engineeringinvestigations of the site area and region should be performed For existing nuclear power plant siteswhere additional units are planned the geosciences technical information originally used to validatethose sites may need to be updated Depending on (1) how much new or additional information hasbecome available since the initial investigations and analyses were performed and (2) the complexity ofthe site and regional geology and seismology additional data may be required This technicalinformation should be used along with all other available information to plan and determine the scopeof additional investigations The investigations described in this regulatory guide are performedprimarily to gather information needed to confirm the suitability of the site and to gather data pertinent tothe safe design and construction of the nuclear power plant Appropriate geological seismological andgeophysical investigations are described in Appendix C to this regulatory guide Geotechnicalinvestigations are described in Regulatory Guide 1132 (Ref 20) Another important purpose for the site-specific investigations is to determine whether there are any new data or interpretations that are notadequately incorporated into the existing PSHA databases Appendix C also describes a method forassessing the impact of new information obtained during the site-specific investigations on the databasesused for the PSHA

These investigations should be performed at four levels with the degree of detail based on (1)distance from the site (2) the nature of the Quaternary tectonic regime (3) the geological complexity ofthe site and region (4) the existence of potential seismic sources and (5) the potential for surfacedeformations etc A more detailed discussion of the areas and levels of investigations and the bases forthem are presented in Appendix C to this regulatory guide General guidelines for the levels ofinvestigation are characterized as follows

111 Within a Radius of 320 Kilometers (200 mi) of the Site (Site Region)

Conduct regional geological and seismological investigations to identify seismic sources Theseinvestigations should include literature reviews the study of maps and remote sensing data and ifnecessary onsite ground-truth reconnaissance

112 Within a Radius of 40 Kilometers (25 mi) of the Site (Site Vicinity)

Geological seismological and geophysical investigations should be carried out in greater detailthan the regional investigations to identify and characterize the seismic and surface deformationpotential of any capable tectonic sources and the seismic potential of seismogenic sources or todemonstrate that such structures are not present Sites with capable tectonic sources within a radius of 40kilometers (km) (25 mi) may require more extensive geological and seismological investigations andanalyses [similar in detail to investigations and analysis usually preferred within an 8 km (5 mi) radius]

113 Within a Radius of 8 Kilometers (5 mi) of the Site (Site Area)

Detailed geological seismological geophysical and geotechnical engineering investigationsshould be conducted to evaluate the potential for tectonic deformation at or near the ground surface andto assess the transmission characteristics of soils and rocks in the site vicinity

RG 1208 Page 12

114 Within a Radius of Approximately 1 Kilometer (06 mi) of the Site (Site Location)

Very detailed geological geophysical and geotechnical engineering investigations should beconducted to assess specific soil and rock characteristics as described in Reference 20

12 Expanding the Areas of Investigation

The areas of investigation may need to be expanded beyond those specified above in regions thatinclude capable tectonic sources relatively high seismicity or complex geology or in regions that haveexperienced a large geologically recent earthquake identified in historical records or by paleoseismicdata

13 Features Discovered During Construction

It should be demonstrated that deformation features discovered during construction (particularlyfaults potential soft zones or other features of engineering significance) do not have the potential tocompromise the safety of the plant The newly identified features should be mapped and assessed as totheir rupture and ground motion generating potential while the excavationsrsquo walls and bases are exposed A commitment should be made in documents (safety analysis reports) supporting the license applicationto geologically map all excavations of significant size and to notify the NRC staff when excavations areopen for inspection This should apply to excavations for construction of all Seismic Category Istructures as a minimum

14 Justifying Assumptions and Conclusions

Data sufficient to clearly justify all assumptions and conclusions should be presented Becauseengineering solutions cannot always be satisfactorily demonstrated for the effects of permanent grounddisplacement it is prudent to avoid a site that has a potential for surface or near-surface deformation Such sites normally will require extensive additional investigations

15 Characterize Lithologic Stratigraphic Hydrologic and Structural Geologic Conditions

For the site and for the area surrounding the site the lithologic stratigraphic hydrologic andstructural geologic conditions should be characterized The investigations should include themeasurement of the static and dynamic engineering properties of the materials underlying the site as wellas an evaluation of the physical evidence concerning the behavior during prior earthquakes of thesurficial materials and the substrata underlying the site The properties needed to assess the behavior ofthe underlying material during earthquakes should be measured These include the potential forliquefaction and the characteristics of the underlying material in transmitting earthquake ground motionsto the foundations of the plant (such as seismic wave velocities density water content porosity elasticmoduli and strength)

RG 1208 Page 13

2 Seismic Sources Significant to the Site Seismic Hazard

21 Evaluation of New Seismic Sources

For sites in the CEUS existing databases may be used to identify seismic sources to performPSHA Previously unidentified seismic sources that were not included in these databases should beappropriately characterized and sensitivity analyses performed to assess their significance to the seismichazard estimate The results of investigation discussed in Regulatory Position 1 should be used inaccordance with Appendix C to this regulatory guide to determine whether the seismic sources and theircharacterization should be updated The guidance in Regulatory Positions 22 and 23 (below) and themethods in Appendix C to this regulatory guide may be used if additional seismic sources are to bedeveloped as a result of investigations

22 Use of Alternative Seismic Sources

When existing methods and databases are not used or are not applicable the guidance inRegulatory Position 23 should be used for identification and characterization of seismic sources Theuncertainties in the characterization of seismic sources should be addressed ldquoSeismic sourcesrdquo is ageneral term that is equivalent to capable tectonic sources

Identification and characterization of seismic sources should be based on regional and sitegeological and geophysical data historical and instrumental seismicity data the regional stress field andgeological evidence of prehistoric earthquakes Investigations to identify seismic sources are describedin Appendix C to this regulatory guide The bases for the identification of seismic sources should bedescribed A general list of characteristics to be evaluated for seismic sources is presented in AppendixC

23 Characterizing Seismic Potential

As part of the seismic source characterization the seismic potential for each source should beevaluated Typically characterization of the seismic potential consists of four equally importantelements

(1) selection of a model for the spatial distribution of earthquakes in a source

(2) selection of a model for the temporal distribution of earthquakes in a source

(3) selection of a model for the relative frequency of earthquakes of various magnitudes includingan estimate for the largest earthquake that could occur in the source under the current tectonicregime

(4) a complete description of the uncertainty

For example truncated exponential and characteristic earthquake models are often used for thedistribution of magnitudes A stationary Poisson process is used to model the spatial and temporaloccurrences of earthquakes in a source For a general discussion of evaluating the earthquake potentialand characterizing the uncertainty refer to NUREGCR-6372 (Ref 9)

RG 1208 Page 14

231 Characterizing Seismic Potential When Alternative Methods and Databases Are Used

For sites in the CEUS the seismic sources and data accepted by the NRC in past licensingdecisions may be used as a starting point along with the data gathered from the investigations carried outas described in Regulatory Position 1

Generally the seismic sources for the CEUS are broad areal source zones because there isuncertainty about the underlying causes of earthquakes This uncertainty is caused by a lack of activesurface faulting a low rate of seismic activity or a short historical record The assessment of earthquakerecurrence for CEUS area sources commonly relies heavily on catalogs of historic earthquakes Becausethese catalogs are incomplete and cover a relatively short period of time the earthquake recurrence ratemay not be estimated reliably Considerable care must be taken to correct for incompleteness and tomodel the uncertainty in the rate of earthquake recurrence To completely characterize the seismicpotential for a source it is also necessary to estimate the largest earthquake magnitude that a seismicsource is capable of generating under the current tectonic regime This estimated magnitude defines theupper bound of the earthquake recurrence relationship

Primary methods for assessing maximum earthquakes for area sources usually include aconsideration of the historical seismicity record the pattern and rate of seismic activity the Quaternarygeologic record (18 million years and younger) characteristics of the source the current stress regime(and how it aligns with known tectonic structures) paleoseismic data and analogs to sources in otherregions considered tectonically similar to the CEUS Because of the shortness of the historical catalogand low rate of seismic activity considerable judgment is needed It is important to characterize thelarge uncertainties in the assessment of the earthquake potential (Refs 9 and 16)

232 Characterizing Seismic Potential for Western United States Sites

For sites located within the WUS earthquakes can often be associated with known tectonicstructures with a high degree of certainty For faults the earthquake potential is related to thecharacteristics of the estimated future rupture such as the total rupture area the length or the amount offault displacement Empirical relations can be used to estimate the earthquake potential from faultbehavior data and also to estimate the amount of displacement that might be expected for a givenmagnitude It is prudent to use several different rupture length or area-versus-magnitude relations toobtain an estimate of the earthquake magnitude When such correlations are used the earthquakepotential is often evaluated as the mean of the distribution The difficult issue is the evaluation of theappropriate rupture dimension to be used This is a judgmental process based on geological data for thefault in question and the behavior of other regional fault systems of the same type

In addition to maximum magnitude other elements of the recurrence model are generallyobtained using catalogs of seismicity fault slip rate and other data Known sources of uncertaintyshould be appropriately modeled

233 Characterizing Seismic Potential for Sites Near Subduction Zones

For sites near subduction zones such as in the Pacific Northwest and Alaska the maximummagnitude must be assessed for subduction zone seismic sources Worldwide observations indicate thatthe largest known earthquakes are associated with the plate boundary interface although intraslabearthquakes may also have large magnitudes The assessment of plate interface earthquakes can be basedon estimates of the expected dimensions of rupture or analogies to other subduction zones worldwide

RG 1208 Page 15

3 Probabilistic Seismic Hazard Analysis Procedures

A PSHA should be performed to allow for the use of multiple source models to estimate thelikelihood of earthquake ground motions occurring at a site and to systematically take into accountuncertainties that exist in various parameters (such as seismic sources maximum earthquakes andground motion attenuation) Alternative hypotheses are considered in a quantitative fashion in a PSHA They can be used to evaluate the sensitivity of the hazard to the uncertainties in the significantparameters and to identify the relative contribution of each seismic source to the hazard

The following steps describe a procedure acceptable to the NRC staff for performing a PSHA

31 Perform Regional and Site Investigations

Perform regional and site geological seismological and geophysical investigations inaccordance with Regulatory Position 1 and Appendix C to this regulatory guide

32 Evaluation of New Information

For CEUS sites perform an evaluation of seismic sources in accordance with Appendix C to thisregulatory guide to determine whether they are consistent with the site-specific data gathered inRegulatory Position 31 or if they require updating The PSHA should be updated if the new informationindicates that the current version of the seismic source model underestimates the hazard or if newattenuation relationships are available In most cases limited-scope sensitivity studies are sufficient todemonstrate that the existing database in the PSHA envelops the findings from site-specificinvestigations Any significant update should follow the guidance of NUREGCR-6372 (Ref 9)

33 Conduct a Probabilistic Seismic Hazard Analysis

Perform a site-specific PSHA with up-to-date interpretations of earthquake sources earthquakerecurrence and strong ground motion estimation using original or updated sources as determined inRegulatory Positions 31 and 32 CAV filtering can be used in place of a lower-bound magnitude cutoffof 50 (Ref 18) For the CEUS the understanding of single- and double-corner ground-motion models isevolving and the PSHA should fully document the appropriateness of using either or both of thesemodels Characterize epistemic uncertainties in a complete and defensible fashion Aleatory variabilityof the ground motion as expressed in the choice of standard deviation of natural log of ground motionused in the PSHA should be considered carefully and described The ground motion estimates should bemade in the free field to develop the seismic hazard information base discussed in Appendix D to thisregulatory guide

34 Hazard Assessment

Report fractile hazard curves at the following fractile levels (p) for each ground motionparameter 005 016 050 084 and 095 as well as the mean Report the fractile hazard curves intabular as well as graphical format Also determine the mean UHRS for annual exceedance frequenciesof 1 E-04 1 E-05 and 1 E-06 at a minimum of 30 structural frequencies approximately equally spaced ona logarithmic frequency axis between 100 and 01 Hz

RG 1208 Page 16

35 Deaggregate the Mean Probabilistic Hazard Characterization

Deaggregate the mean probabilistic hazard characterization at ground motion levelscorresponding to the annual frequencies of 1 E-04 1 E-05 and 1 E-06 in accordance with Appendix D tothis regulatory guide Deaggregation provides information useful for review of the PSHA and insightinto the seismic sources that most impact the hazard at a particular site It can also be used to determinethe controlling earthquakes (ie magnitudes and distances) and document the hazard information base asdiscussed in Appendix D

4 Seismic Wave Transmission Characteristics of the Site

The hazard curves from the PSHA are defined for general surficial rock conditions that areconsistent with the definition of rock for the attenuation relationships used in the PSHA For exampleexisting attenuation relationships for the CEUS typically define generic rock conditions as materials witha shear wave velocity (Vs) of 28 kmsec (9200 ftsec) Because the surficial and subsurface shear wavevelocities at nuclear power plant sites are generally less than those for the generic rock conditions thefollowing procedures should be used to define the UHRS at the free-field ground surface Additionaldiscussion pertaining to this regulatory position is provided in Appendix E to this regulatory guide

For both soil and rock sites the subsurface model should extend to sufficient depth to reach thegeneric rock conditions as defined in the attenuation relationships used in the PSHA

41 Site and Laboratory Investigations and Testing

Perform site and laboratory investigations and testing to obtain data defining the static anddynamic engineering properties of the site-specific soil and rock materials Consideration should begiven to spatial distribution both within individual geologic strata and across the site Methodsacceptable to the NRC staff are described in Regulatory Guide 1132 (Ref 20) Regulatory Guide 1138(Ref 21) and Subsection C222 of Appendix C to this regulatory guide Sufficient site property datashould be developed to adequately estimate the mean and variability of the properties in the site responsecalculations When soil models are deduced from laboratory studies the sampling and testing programsshould be critically peer reviewed to ensure that the generated soil dynamic nonlinear properties areappropriate to properly characterize site response

42 Dynamic Site Response

Using the site-specific dynamic properties of the soil and information on hazard levels from therock-based site-specific UHRS the dynamic site response should be determined through analyses basedon either time history or random vibration theory (RVT) If a time history-based procedure is used it isnecessary to determine an appropriate set of ground motions or earthquake time histories for each of thetarget response spectra to be analyzed A sufficient number of time histories should be used to obtainconsistent average behavior from the dynamic site response analyses The target response spectra may bebased on Controlling Earthquakes as discussed in Appendix E

RVT methods characterize the input rock motion using a Fourier amplitude spectrum instead oftime domain earthquake input motions This spectrum is propagated through the soil to the surface usingfrequency domain transfer functions and computing peak ground accelerations or spectral accelerationsusing extreme value statistics In the past traditional site response analyses using time histories has beenmost prevalent However RVT methods are acceptable as long as the strain dependent soil propertiesare adequately accounted for in the analysis

RG 1208 Page 17

Reference 6 contains a database of recorded time histories on rock for both the CEUS and WUSto be used as seed motions for site response analyses The database is divided into magnitude anddistance bins with each bin having a minimum of 15 three-component (two horizontal and one vertical)sets If these records are used as seed motions they should be developed consistent with therecommendations in Reference 6 Appendix F to this regulatory guide provides criteria acceptable to theNRC staff for developing and evaluating sets of modified ground motions used for soil response andstructural analyses The time histories are scaled or spectrally matched to match the response spectrumand have characteristics appropriate for the corresponding target response spectrum

Often vertically propagating shear waves are the dominant contributor to free-field groundmotions at a site In these cases a one-dimensional equivalent-linear analysis or nonlinear analysis thatassumes vertical propagation of shear waves may be appropriate However site characteristics (such as adipping bedrock surface topographic effects or other impedance boundaries) regional characteristics(such as certain topographic effects) and source characteristics (such as nearby dipping seismic sources)may require that analyses are also able to account for inclined waves

A Monte Carlo or equivalent procedure should be used to accommodate the variability in soildepth shear wave velocities layer thicknesses and strain-dependent dynamic nonlinear materialproperties at the site A sufficient number of convolution analyses should be performed using scaledearthquake time histories to adequately capture the effect of the site subsurface variability and theuncertainty in the soil properties Generally at least 60 convolution analyses should be performed todefine the mean and the standard deviation of the site response The results of the site response analysesare used to develop high- and low-frequency site amplification functions as detailed in Appendix E tothis regulatory guide

43 Site Amplification Function

Based on the site response analyses described in Regulatory Position 42 site amplificationfunctions are calculated To determine the UHRS at the free-field ground surface for a specific annualprobability of exceedance multiply the rock-based UHRS by either the high-frequency or low-frequencysite amplification functions as appropriate for each frequency The appropriate site amplificationfunction is determined for each frequency based on which of the controlling or input earthquakes has aspectral value that is closest to the rock UHRS at that frequency At high frequencies this will be thehigh-frequency spectral amplification function and at low-frequencies the low-frequency siteamplification function By applying the appropriate (high- or low-frequency) amplification function foreach frequency to the mean rock-based UHRS the site-specific soil-based UHRS is calculated for thefree ground surface The surface 1 E-04 and 1 E-05 UHRS are site-specific earthquake ground motionsthat form the basis of the performance-based site GMRS

5 Performance-Based Site-Specific Earthquake Ground Motion Procedure

51 Horizontal Spectrum

The performance-based site-specific earthquake ground motion is developed using a methodanalogous to the development of the ASCESEI Standard 43-05 (Ref 7) design response spectrum (DRS)

Fthat achieves the annual FOSID target performance goal (P ) of 1 E-05 and hazard exceedance

Dprobability (H ) of 1 E-04 described in Chapters 1 and 2 of Reference 7 and also discussed in Section Bof this guide The horizontal site-specific performance-based GMRS are obtained by scaling the site-specific mean UHRS by a design factor (DF) or

RG 1208 Page 18

GMRS = UHRS x DF Equation (1)

where UHRS is the mean 1 E-04 UHRS derived in accordance with Regulatory Position 43 andDF (from Reference 7) is

RDF = max 10 06(A ) Equation (2)08

Rwhere A is the ground motion slope ratio of spectral accelerations frequency by frequencyfrom a seismic hazard curve corresponding to a 10-fold reduction in hazard exceedance frequencytherefore

RA = mean 1 E-05 UHRS divide mean 1 E-04 UHRS Equation (3)

Figure 2 provides a comparison of the performance-based site-specific horizontal GMRS and themean 1 E-04 and 1 E-05 UHRS

The above is based on the assumption that the hazard curves are approximated by a power law

Requation (ie linear on a log-log plot) in the range of 1 E-04 to 1 E-05 If A is greater than 42 then thisassumption is not valid In these cases it is acceptable to use a value equal to 45 percent of the mean 1E-05 UHRS Using this method results in a GMRS that achieves the annual FOSID target of 1 E-05

52 Vertical Spectrum

Vertical response spectra are developed by combining the appropriate horizontal responsespectra and the most up-to-date VH response spectral ratios appropriate for either CEUS or WUS sites Appropriate VH ratios for CEUS or WUS rock and soil sites are best determined from the most up-to-date attenuation relations However as there are currently no CEUS attenuation relations that predictvertical ground motions appropriate VH ratios for CEUS rock sites provided in Reference 6 may beused For CEUS soil sites References 6 and 22 describe a procedure to determine a WUS-to-CEUStransfer function that may be used to modify the WUS VH soil ratios Other methods used to determineVH ratios may also be appropriate

53 Location of the Site Ground Motion Response Spectrum

The horizontal and vertical GMRS are determined in the free field on the ground surface Forsites with soil layers near the surface that will be completely excavated to expose competent material theGMRS are specified on the outcrop or hypothetical outcrop that will exist after excavation Motions atthis hypothetical outcrop should be developed as a free surface motion not as an in-column motion Although the definition of competent material is not mandated by regulation a number of reactor designshave specified a shear wave velocity of 1000 fps as the definition of competent material When theGMRS are determined as free-field outcrop motions on the uppermost in-situ competent material onlythe effects of the materials below this elevation are included in the site response analysis

RG 1208 Page 19

54 Determination of Safe Shutdown Earthquake

The SSE is the vibratory ground motion for which certain structures systems and componentsare designed to remain functional pursuant to Appendix S to 10 CFR Part 50 The SSE for the site ischaracterized by both horizontal and vertical free-field ground motion response spectra at the free groundsurface The purpose of this regulatory guide is to provide guidance on the development of thesite-specific GMRS The GMRS satisfy the requirements of 10 CFR 10023 with respect to thedevelopment of the SSE In the performance-based approach described in this guide the GMRS arebased on the site-specific UHRS at the free-field ground surface modified by a design factor to obtain theperformance-based site-specific response spectrum The design factor achieves a relatively consistentannual probability of plant component failure across the range of plant locations and structuralfrequencies

The steps necessary to develop the final SSE are described in Chapter 3 ldquoDesign of StructuresComponents Equipment and Systemsrdquo of NUREG-0800 ldquoStandard Review Planrdquo This process isdefined by two distinct options The first option is for COL applicants using a standard design nuclearpower plant The standard designs use broad-band smooth response spectra referred to as certifiedseismic design response spectra (CSDRS) The CSDRS are site-independent seismic design responsespectra scaled to a peak ground motion value Under the first option or combined license procedure theGMRS are used to determine the adequacy of the CSDRS for the site If adequate the CSDRS becomethe SSE for the site Alternatively under the second option an applicant would develop a site-specificnuclear power plant design based on a site SSE For some sites the GMRS may not contain adequateenergy in the frequency range of engineering interest and therefore may not be appropriate as thesite-specific plant SSE For these situations the GMRS could either be broadened or enveloped by asmoothed spectrum

During the design phase an additional check of the ground motion is required at the foundationlevel According to Appendix S to 10 CFR Part 50 the foundation level ground motion must berepresented by an appropriate response spectrum with a peak ground acceleration of at least 01g Thesteps necessary to determine the final SSE such as the acceptability of the CSDRS for a given site andthe minimum seismic design-basis requirements are described in Chapter 3 of NUREG-0800

RG 1208 Page 20

Figure 2 Comparison of the Mean 1 E-04 and 1 E-05 Uniform Hazard Response |Spectra and the Performance-Based Ground Motion Response Spectrum (GMRS) |

|

Mean UHRS 1E-5Mean UHRS 1E-4Performance-Based GMRS

RG 1208 Page 21

D IMPLEMENTATION

The purpose of this section is to provide information to applicants regarding the NRC staffrsquosplans for using this regulatory guide No backfitting is intended or approved in connection with itsissuance

This regulatory guide identifies methods that the NRC staff considers acceptable for (1)conducting geological geophysical seismological and geotechnical investigations (2) identifying andcharacterizing seismic sources (3) conducting probabilistic seismic hazard analyses (4) determiningseismic wave transmission characteristics of soil and rock sites and (5) determining a performance-basedsite-specific GMRS for satisfying the requirements of 10 CFR 10023 A brief overview of techniquesto develop the SSE in order to satisfy the requirements of Appendix S to 10 CFR Part 50 is also includedin this guide and in NUREG-0800 ldquoStandard Review Planrdquo Section 371

REGULATORY ANALYSIS BACKFIT ANALYSIS

The regulatory analysis and backfit analysis for this regulatory guide are available in DraftRegulatory Guide DG-1146 ldquoA Performance-Based Approach to Define the Site-Specific EarthquakeGround Motionrdquo (Ref 23) The NRC issued DG-1146 in October 2006 to solicit public comment on thedraft version of Regulatory Guide 1208

All NRC regulations listed herein are available electronically through the Public Electronic Reading Room on the4

NRCrsquos public Web site at httpwwwnrcgovreading-rmdoc-collectionscfr Copies are also available for inspectionor copying for a fee from the NRCrsquos Public Document Room at 11555 Rockville Pike Rockville MD the PDRrsquosmailing address is USNRC PDR Washington DC 20555 telephone (301) 415-4737 or (800) 397-4209 fax (301)415-3548 email PDRnrcgov

All NUREG-series reports listed herein were published by the US Nuclear Regulatory Commission Copies are5

available for inspection or copying for a fee from the NRCrsquos Public Document Room at 11555 Rockville PikeRockville MD the PDRrsquos mailing address is USNRC PDR Washington DC 20555 telephone (301) 415-4737 or(800) 397-4209 fax (301) 415-3548 email PDRnrcgov Copies are also available at current rates from the USGovernment Printing Office PO Box 37082 Washington DC 20402-9328 telephone (202) 512-1800 or from theNational Technical Information Service (NTIS) at 5285 Port Royal Road Springfield Virginia 22161 online athttpwwwntisgov by telephone at (800) 553-NTIS (6847) or (703) 605-6000 or by fax to (703) 605-6900 NUREG-0800 is also available electronically through the Electronic Reading Room on the NRCrsquos public Web site athttpwwwnrcgov reading-rmdoc-collectionsnuregs

All regulatory guides listed herein were published by the US Nuclear Regulatory Commission Where an accession6

number is identified the specified regulatory guide is available electronically through the NRCrsquos AgencywideDocuments Access and Management System (ADAMS) at httpwwwnrcgovreading-rmadamshtml All otherregulatory guides are available electronically through the Public Electronic Reading Room on the NRCrsquos public Website at httpwwwnrcgovreading-rmdoc-collectionsreg-guides Single copies of regulatory guides may also beobtained free of charge by writing the Reproduction and Distribution Services Section ADM USNRC WashingtonDC 20555-0001 or by fax to (301) 415-2289 or by email to DISTRIBUTIONnrcgov Active guides may also bepurchased from the National Technical Information Service (NTIS) on a standing order basis Details on this servicemay be obtained by contacting NTIS at 5285 Port Royal Road Springfield Virginia 22161 online athttpwwwntisgov by telephone at (800) 553-NTIS (6847) or (703) 605-6000 or by fax to (703) 605-6900 Copiesare also available for inspection or copying for a fee from the NRCrsquos Public Document Room (PDR) which is locatedat 11555 Rockville Pike Rockville Maryland the PDRrsquos mailing address is USNRC PDR Washington DC 20555-0001 The PDR can also be reached by telephone at (301) 415-4737 or (800) 397-4209 by fax at (301) 415-3548 andby email to PDRnrcgov

RG 1208 Page 22

REFERENCES

1 US Code of Federal Regulations Title 10 Energy Part 100 ldquoReactor Site Criteriardquo4

2 US Code of Federal Regulations Title 10 Energy Part 50 ldquoDomestic Licensing of Productionand Utilization Facilitiesrdquo5

3 US Code of Federal Regulations Title 10 Energy Part 52 ldquoLicenses Certifications andApprovals for Nuclear Power Plantsrdquo5

4 NUREG-0800 ldquoStandard Review Plan for the Review of Safety Analysis Reports for NuclearPower Plantsrdquo US Nuclear Regulatory Commission Washington DC5

5 Regulatory Guide 1165 ldquoIdentification and Characterization of Seismic Sources andDetermination of Safe Shutdown Earthquake Ground Motionrdquo US Nuclear RegulatoryCommission Washington DC6

Copies are available for inspection or copying for a fee from the NRCrsquos Public Document Room at 11555 Rockville7

Pike Rockville MD the PDRrsquos mailing address is USNRC PDR Washington DC 20555 telephone (301) 415-4737or (800) 397-4209 fax (301) 415-3548 email PDRnrcgov In addition copies are available at current rates fromthe US Government Printing Office PO Box 37082 Washington DC 20402-9328 telephone (202) 512-1800 orfrom the National Technical Information Service (NTIS) at 5285 Port Royal Road Springfield Virginia 22161 onlineat httpwwwntisgov by telephone at (800) 553-NTIS (6847) or (703) 605-6000 or by fax to (703) 605-6900

Copies may be purchased from the American Society for Civil Engineers (ASCE) 1801 Alexander Bell Drive Reston8

VA 20190 [phone 800-548-ASCE (2723)] Purchase information is available through the ASCE Web site at httpwwwasceorgbookstorebookcfmisbn=0784407622


Pike Rockville MD the PDRrsquos mailing address is USNRC PDR Washington DC 20555 telephone (301) 415-4737or (800) 397-4209 fax (301) 415-3548 email PDRnrcgov

RG 1208 Page 23

6 McGuire RK WJ Silva and CJ Costantino ldquoTechnical Basis for Revision of RegulatoryGuidance on Design Ground Motions Hazard- and Risk-Consistent Ground Motion SpectraGuidelinesrdquo NUREGCR-6728 US Nuclear Regulatory Commission Washington DCOctober 20017

7 ASCESEI 43-05 ldquoSeismic Design Criteria for Structures Systems and Components in NuclearFacilitiesrdquo American Society of Civil EngineersStructural Engineering Institute 20058

8 Regulatory Guide 160 ldquoDesign Response Spectra for Seismic Design of Nuclear Power PlantsrdquoUS Nuclear Regulatory Commission7

9 Budnitz RJ et al ldquoRecommendations for Probabilistic Seismic Hazard Analysis Guidance onUncertainty and Use of Expertsrdquo NUREGCR-6372 Volumes 1 and 2 US Nuclear RegulatoryCommission Washington DC April 19978

10 Pacific Gas and Electric Company ldquoFinal Report of the Diablo Canyon Long-Term SeismicProgram Diablo Canyon Power Plantrdquo Docket Nos 50-275 and 50-323 19889

11 Rood H et al ldquoSafety Evaluation Report Related to the Operation of Diablo Canyon NuclearPower Plant Units 1 and 2rdquo NUREG-0675 Supplement No 34 US Nuclear RegulatoryCommission Washington DC June 19918

12 Sorensen G Washington Public Power Supply System Letter to Document Control BranchUS Nuclear Regulatory Commission Washington DC Subject ldquoNuclear Project No 3Resolution of Key Licensing Issues Responserdquo February 29 198810

13 Bernreuter DL et al ldquoSeismic Hazard Characterization of 69 Nuclear Plant Sites East of theRocky Mountainsrdquo NUREGCR-5250 Volumes 1ndash8 US Nuclear Regulatory CommissionWashington DC January 19898

14 Sobel P ldquoRevised Livermore Seismic Hazard Estimates for Sixty-Nine Nuclear Power PlantSites East of the Rocky Mountainsrdquo NUREG-1488 US Nuclear Regulatory CommissionWashington DC April 19948

15 Savy JB et al ldquoEastern Seismic Hazard Characterization Updaterdquo UCRL-ID-115111Lawrence Livermore National Laboratory June 1993 (Accession 9310190318 in the NRCrsquosPublic Document Room)10

Draft Regulatory Guide DG-1146 is available electronically under Accession ML063030291 in the NRCrsquos10

Agencywide Documents Access and Management System (ADAMS) at httpwwwnrcgovreading-rmadamshtml Copies are also available for inspection or copying for a fee from the NRCrsquos Public Document Room (PDR) which islocated at 11555 Rockville Pike Rockville Maryland the PDRrsquos mailing address is USNRC PDR Washington DC20555-0001 The PDR can also be reached by telephone at (301) 415-4737 or (800) 397-4209 by fax at (301) 415-3548 and by email to PDRnrcgov

RG 1208 Page 24

16 Electric Power Research Institute (EPRI) ldquoProbabilistic Seismic Hazard Evaluations at NuclearPower Plant Sites in the Central and Eastern United Statesrdquo NP-4726 All Volumes 1989ndash1991

17 Electric Power Research Institute (EPRI) ldquoThe Earthquakes of Stable Continental RegionsrdquoVolume 1 Assessment of Large Earthquake Potential EPRI TR-102261-V1 1994

18 Electric Power Research Institute (EPRI) and US Department of Energy (DOE) ldquoProgram onTechnology Innovation Use of Minimum CAV in Determining Effects of Small MagnitudeEarthquakes on Seismic Hazard Analysesrdquo Report 1012965 December 2005

19 Electric Power Research Institute (EPRI) and US Department of Energy (DOE) ldquoProgram onTechnology Innovation Truncation of the Lognormal Distribution and Value of the StandardDeviation for Ground Motion Models in the Central and Eastern United Statesrdquo Report 1013105February 2006

20 Regulatory Guide 1132 ldquoSite Investigations for Foundations of Nuclear Power Plantsrdquo USNuclear Regulatory Commission Washington DC7

21 Regulatory Guide 1138 ldquoLaboratory Investigations of Soils and Rocks for Engineering Analysisand Design of Nuclear Power Plantsrdquo US Nuclear Regulatory Commission Washington DC7

22 McGuire RK WJ Silva and CJ Costantino ldquoTechnical Basis for Revision of RegulatoryGuidance on Design Ground Motions Development of Hazard- and Risk-Consistent SeismicSpectra for Two Sitesrdquo NUREGCR-6769 US Nuclear Regulatory Commission WashingtonDC April 20028

23 Draft Regulatory Guide DG-1146 ldquoA Performance-Based Approach to Define the Site-SpecificEarthquake Ground Motionrdquo US Nuclear Regulatory Commission Washington DC10

Appendix A to RG 1208 Page A-1

APPENDIX A

DEFINITIONS

Accepted PSHA Model An accepted PSHA model is a method of conducting a Probabilistic SeismicHazard Analysis (including the seismic sources and ground motion equations) that has been developedusing Senior Seismic Hazard Analysis Committee (SSHAC) guidelines and that has been reviewed andaccepted by the NRC in the past either for generic application (eg the 1989 studies by LLNL and EPRIwith the inherent seismic source description for the CEUS) or as part of an ESP or COL application Accepted PSHA models are starting points for developing probabilistic seismic hazard calculations fornew ESP or COL applications yet must be updated with new information on seismicity geologygeophysics and ground motion equations as appropriate for a site that is being reviewed The termaccepted PSHA model should not be assumed to imply that the model can be used without updates orreviews as discussed RG 1208

Capable Tectonic Source A capable tectonic source is a tectonic structure that can generate bothvibratory ground motion and tectonic surface deformation such as faulting or folding at or near the earthssurface in the present seismotectonic regime It is described by at least one of the followingcharacteristics

(1) presence of surface or near-surface deformation of landforms or geologic deposits of a recurringnature within the last approximately 500000 years or at least once in the last approximately50000 years

(2) a reasonable association with one or more moderate to large earthquakes or sustained earthquakeactivity that are usually accompanied by significant surface deformation

(3) a structural association with a capable tectonic source that has characteristics of either item a or b(above) such that movement on one could be reasonably expected to be accompanied bymovement on the other

In some cases the geological evidence of past activity at or near the ground surface along a potentialcapable tectonic source may be obscured at a particular site This might occur for example at a sitehaving a deep overburden For these cases evidence may exist elsewhere along the structure from whichan evaluation of its characteristics in the vicinity of the site can be reasonably based Such evidence is tobe used in determining whether the structure is a capable tectonic source within this definitionNotwithstanding the foregoing paragraphs the association of a structure with geological structures thatare at least pre-Quaternary such as many of those found in the central and eastern regions of the UnitedStates in the absence of conflicting evidence will demonstrate that the structure is not a capable tectonicsource within this definition

Certified Seismic Design Response Spectra (CSDRS) Site-independent seismic design responsespectra that have been approved under Subpart B of 10 CFR Part 52 as the seismic design responsespectra for an approved certified standard design nuclear power plant The input or control location forthe CSDRS is specified in the certified standard design


Combined License A combined construction permit and operating license with conditions for a nuclearpower facility issued pursuant to Subpart C of 10 CFR Part 52

Controlling Earthquakes Earthquakes used to determine spectral shapes or to estimate ground motionsat the site for some methods of dynamic site response There may be several controlling earthquakes fora site As a result of the probabilistic seismic hazard analysis (PSHA) controlling earthquakes arecharacterized as mean magnitudes and distances derived from a deaggregation analysis of the meanestimate of the PSHA

Cumulative Absolute Velocity (CAV) For each component of the free-field ground motion the CAVshould be calculated as follows (1) the absolute acceleration (g units) time-history is divided into1-second intervals (2) each 1-second interval that has at least 1 exceedance of 0025g is integrated overtime and (3) all the integrated values are summed together to arrive at the CAV The CAV is exceededif the calculation is greater than 016 g-second The application of the CAV in siting requires thedevelopment of a CAV model (Ref 18) because the PSHA calculation does not use time historiesdirectly

Deaggregation The process for determining the fractional contribution of each magnitude-distance pairto the total seismic hazard To accomplish this a set of magnitude and distance bins are selected and theannual probability of exceeding selected ground acceleration parameters from each magnitude-distancepair is computed and divided by the total probability for earthquakes

Design Factor The ratio between the site-specific GMRS and the UHRS The design factor is aimed atachieving the target annual probability of failure associated with the target performance goals

Early Site Permit A Commission approval issued pursuant to Subpart A of 10 CFR Part 52 for a siteor sites for one or more nuclear power facilities

Earthquake Recurrence The frequency of occurrence of earthquakes as a function of magnitude Recurrence relationships or curves are developed for each seismic source and they reflect the frequencyof occurrence (usually expressed on an annual basis) of magnitudes up to the maximum includingmeasures of uncertainty

Frequency of Onset of Significant Inelastic Deformation (FOSID) The annual probability of theonset of significant inelastic deformation (OSID) OSID is just beyond the occurrence of insignificant(or localized) inelastic deformation and in this way corresponds to ldquoessentially elastic behaviorrdquo Assuch OSID of a structure system or component (SSC) can be expected to occur well before seismicallyinduced core damage resulting in much larger frequencies of OSID than seismic core damage frequency(SCDF) values In fact OSID occurs before SSC ldquofailurerdquo where the term failure refers to impairedfunctionality

Ground Motion Response Spectra (GMRS) A site-specific ground motion response spectracharacterized by horizontal and vertical response spectra determined as free-field motions on the groundsurface or as free-field outcrop motions on the uppermost in-situ competent material usingperformance-based procedures When the GMRS are determined as free-field outcrop motions on theuppermost in-situ competent material only the effects of the materials below this elevation are includedin the site response analysis


Ground Motion Slope Ratio Ratio of the spectral accelerations frequency by frequency from aseismic hazard curve corresponding to a 10-fold reduction in hazard exceedance frequency (SeeEquation 3 in Regulatory Position 51)

In-column Motion Motion that is within a soil column as opposed to the motion at the surface ortreated as if it is at the surface

Intensity The intensity of an earthquake is a qualitative description of the effects of the earthquake at aparticular location as evidenced by observed effects on humans on human-built structures and on theearthrsquos surface at a particular location Commonly used scales to specify intensity are the Rossi-ForelMercalli and Modified Mercalli The Modified Mercalli Intensity (MMI) scale describes intensities withvalues ranging from I to XII in the order of severity MMI of I indicates an earthquake that was not feltexcept by a very few whereas MMI of XII indicates total damage of all works of construction eitherpartially or completely

Magnitude An earthquakersquos magnitude is a measure of the strength of the earthquake as determinedfrom seismographic observations and is an objective quantitative measure of the size of an earthquake The magnitude can be expressed in various ways based on seismographic records (eg Richter LocalMagnitude Surface Wave Magnitude Body Wave Magnitude and Moment Magnitude) Currently the

wmost commonly used magnitude measurement is the Moment Magnitude M which is based on theseismic moment computed as the rupture force along the fault multiplied by the average amount of slipand thus is a direct measure of the energy released during an earthquake

Maximum Magnitude The maximum magnitude is the upper bound to earthquake recurrence curves

Mean Site Amplification Function The mean amplification function is obtained for each controllingearthquake by dividing the response spectrum from the computed surface motion by the responsespectrum from the input hard rock motion and computing the arithmetic mean of the individual responsespectral ratios

Nontectonic Deformation Nontectonic deformation is distortion of surface or near-surface soils orrocks that is not directly attributable to tectonic activity Such deformation includes features associatedwith subsidence karst terrain glaciation or deglaciation and growth faulting

Response Spectrum A plot of the maximum responses (acceleration velocity or displacement) ofidealized single-degree-of-freedom oscillators as a function of the natural frequencies of the oscillatorsfor a given damping value The response spectrum is calculated for a specified vibratory motion input atthe oscillatorsrsquo supports

Ring Area Annular region bounded by radii associated with the distance rings used in hazarddeaggregation (Table D1 ldquoRecommended Magnitude and Distance Binsrdquo in Appendix D to thisregulatory guide)

Safe Shutdown Earthquake Ground Motion (SSE) The vibratory ground motion for which certainstructures systems and components are designed pursuant to Appendix S to 10 CFR Part 50 to remainfunctional The SSE for the site is characterized by both horizontal and vertical free-field ground motionresponse spectra at the free ground surface


Seismic Wave Transmission (Site Amplification) The amplification (increase or decrease) ofearthquake ground motion by rock and soil near the earthrsquos surface in the vicinity of the site of interest Topographic effects the effect of the water table and basin edge wave-propagation effects are sometimesincluded under site response

Seismogenic Source A portion of the earth that is assumed to have a uniform earthquake potential(same expected maximum earthquake and recurrence frequency) distinct from that of surroundingsources A seismogenic source will generate vibratory ground motion but is assumed to not cause surfacedisplacement Seismogenic sources cover a wide range of seismotectonic conditions from a well-definedtectonic structure to simply a large region of diffuse seismicity

Spectral Acceleration Peak acceleration response of an oscillator as a function of period or frequencyand damping ratio when subjected to an acceleration time history It is equal to the peak relativedisplacement of a linear oscillator of frequency f attached to the ground times the quantity (2Bf) It is2

expressed in units of gravity (g) or cmsecond 2

Stable Continental Region (SCR) An SCR is composed of continental crust including continentalshelves slopes and attenuated continental crust and excludes active plate boundaries and zones ofcurrently active tectonics directly influenced by plate margin processes It exhibits no significantdeformation associated with the major Mesozoic-to-Cenozoic (last 240 million years) orogenic belts Itexcludes major zones of Neogene (last 25 million years) rifting volcanism or suturing

Stationary Poisson Process A probabilistic model of the occurrence of an event over time (or space)that has the following characteristics (1) the occurrence of the event in small intervals is constant overtime (or space) (2) the occurrence of two (or more) events in a small interval is negligible and (3) theoccurrence of the event in non-overlapping intervals is independent

FTarget Performance Goal (P ) Target annual probability of exceeding the 1 E-05 frequency of onsetof significant inelastic deformation (FOSID) limit state

Tectonic Structure A large-scale dislocation or distortion usually within the earthrsquos crust Its extentmay be on the order of tens of meters (yards) to hundreds of kilometers (miles)

Uniform Hazard Response Spectrum (UHRS) A plot of a ground response parameter (for examplespectral acceleration or spectral velocity) that has an equal likelihood of exceedance at differentfrequencies

Within Motion An earthquake record modified for use in a site response model Within motions aredeveloped through deconvolution of a surface recording to account for the properties of the overburdenmaterial at the level at which the record is to be applied The within motion can also be called theldquobedrock motionrdquo if it occurs at a high-impedance boundary where rock is first encountered

Appendix B to RG 1208 Page B-1

APPENDIX B

ABBREVIATIONS

A peak ground accelerationADAMS Agencywide Documents Access and Management System (NRC)

RA ground motion slope ratioASCE American Society of Civil EngineersASTM American Society of Testing and Materials

CAV cumulative absolute velocityCFR Code of Federal RegulationsCP construction permitCEUS central and eastern United StatesCOL combined licenseCSDRS certified seismic design response spectra

D distanceD peak ground displacementDF design factorDOE US Department of EnergyDRS design response spectrum

EPRI Electric Power Research InstituteESP early site permit

FIRS foundation input response spectraFOSID frequency of onset of significant inelastic deformation

GMRS ground motion response spectra

DH mean annual hazard exceedance frequencyprobability

IAEA International Atomic Energy Agency

LLNL Lawrence Livermore National Laboratory

M magnitudeMMI Modified Mercalli Intensity

NGA Next Generation AttenuationNRC US Nuclear Regulatory Commission

OL operating licenseOMB Office of Management and BudgetOSID onset of significant inelastic deformation


FP target performance goalPDR Public Document Room (NRC)PGA peak ground accelerationPGV peak ground velocityPSHA probabilistic seismic hazard analysis

PR probability ratioRVT random vibration theory

SCDF seismic core damage frequencySCR stable continental regionSDC seismic design categorySRP Standard Review Plan (NUREG-0800)SSCs structures systems and componentsSSE safe shutdown earthquake ground motionSSHAC Senior Seismic Hazard Analysis CommitteeStandard ASCESEI Standard 43-05 (Ref 7)

UHRS uniform hazard response spectrumUSNRC US Nuclear Regulatory Commission

V peak ground velocityVH ratio of vertical to horizontal spectral accelerations

sV shear wave velocity

WUS western United States

Appendix C to RG 1208 Page C-1

APPENDIX C

INVESTIGATIONS TO CHARACTERIZESITE GEOLOGY SEISMOLOGY AND GEOPHYSICS

C1 Introduction

As characterized for use in probabilistic seismic hazard analyses (PSHA) seismogenic sourcesare zones within which future earthquakes are likely to occur Geological seismological andgeophysical investigations provide the information needed to identify and characterize source zoneparameters such as size and geometry and to estimate earthquake recurrence rates and maximummagnitudes The amount of data available about earthquakes and their causative sources variessubstantially between the western United States (WUS) (west of the Rocky Mountain front) and thecentral and eastern United States (CEUS) or stable continental region (east of the Rocky Mountainfront) Furthermore there are variations in the amount and quality of data within these regions

Seismogenic sources in active tectonic regions such as the WUS are generally readily identifiedbecause of their relatively high activity rate In the CEUS identifying seismogenic sources is moredifficult because their activity rate is relatively low and because most seismic sources are covered bythick deposits However several significant tectonic structures exist and some of these have beeninterpreted as seismogenic sources (eg the New Madrid fault zone Nemaha Ridge and Meers fault)

In the CEUS it is most likely that the determination of the properties of the seismogenic sourcewhether it is a tectonic structure or a broad areal source zone will be inferred rather than demonstratedby strong correlations with seismicity or geologic data Moreover it is not generally known whatrelationships exist between observed tectonic structures in a seismic source within the CEUS and thecurrent earthquake activity that may be associated with that source The historical seismicity record theresults of regional and site studies and expert judgment play key roles in characterizing a source zone If on the other hand strong correlations and data exist suggesting a relationship between seismicity andseismic sources approaches used for more active tectonic regions can be applied Reference C1 may beused to assess potential for large earthquakes

The primary objective of geological seismological and geophysical investigations is to developan up-to-date site-specific earth science database that supports site characterization and a site-specificPSHA The results of these investigations will also be used to assess whether new data and theirinterpretation are consistent with the information used in recent probabilistic seismic hazard studiesaccepted by NRC staff If new data such as new seismic sources and new ground motion attenuationrelationships are consistent with the existing earth science database updating or modification of theinformation used in the site-specific hazard analysis is not required It will be necessary to updateseismic sources and ground motion attenuation relationships for sites where there is significant newinformation provided by the site investigation


The following are to be evaluated for seismic source characterization

bull Evaluation of seismic source location and geometry (location and extent both surface andsubsurface) This evaluation will normally require interpretations of available geologicalgeophysical and seismological data in the source region by multiple experts or a team of experts The evaluation should include interpretations of the seismic potential of each source andrelationships among seismic sources in the region to express uncertainty in the evaluations Seismic source evaluations generally develop four types of sources (1) fault sources (2) areasources representing concentrated historic seismicity not associated with known tectonicstructure (3) area sources representing geographic regions with similar tectonic histories type ofcrust and structural features and (4) background sources Background sources are generallyused to express uncertainty in the overall seismic source configuration interpreted for the siteregion Acceptable approaches for evaluating and characterizing uncertainties for input to aseismic hazard calculation are contained in NUREGCR-6372 (Ref C2)

bull Evaluations of earthquake recurrence for each seismic source including recurrence rate andrecurrence model These evaluations normally draw most heavily on historical and instrumentalseismicity associated with each source and paleoearthquake information Preferred methods andapproaches for evaluating and characterizing uncertainty in earthquake recurrence generally willdepend on the type of source Acceptable methods are described in NUREGCR-6372 (RefC2)

bull Evaluations of the maximum earthquake magnitude for each seismic source These evaluationswill draw on a broad range of source-specific tectonic characteristics including tectonic historyand available seismicity data Uncertainty in this evaluation should normally be expressed as amaximum magnitude distribution Preferred methods and information for evaluating andcharacterizing maximum earthquakes for seismic sources vary with the type of source Acceptable methods are contained in NUREGCR-6372 (Ref C2)

bull Other evaluations depending on the geologic setting of a site such as local faults that have ahistory of Quaternary (last 18 million years) displacements sense of slip on faults fault lengthand width area of faults age of displacements estimated displacement per event estimatedearthquake magnitude per offset event orientations of regional tectonic stresses with respect tofaults and the possibility of seismogenic folds Capable tectonic sources are not always exposedat the ground surface (such as blind thrust faults) in the WUS as demonstrated by the buriedreverse causative faults of the 1983 Coalinga 1988 Whittier Narrows l989 Loma Prieta and1994 Northridge earthquakes These examples emphasize the need to conduct thoroughinvestigations not only at the ground surface but also in the subsurface to identify structures atseismogenic depths Regional topographic features should also be closely studied Wheneverfaults or other structures are encountered at a site (including sites in the CEUS) in either outcropor excavations it is necessary to perform adequately detailed specific investigations to determinewhether or not they are seismogenic or may cause surface deformation at the site Acceptablemethods for performing these investigations are contained in NUREGCR-5503 (Ref C3)


C2 Investigations To Evaluate Seismic Sources

C21 General

Investigations of the site and region around the site are necessary to identify capable tectonicsources and to determine their potential for generating earthquakes and causing surface deformation If itis determined that surface deformation need not be taken into account at the site sufficient data to clearlyjustify this determination should be presented in the application for an early site permit or license Generally any tectonic deformation at the earthrsquos surface within the Site Area [8 km (5 mi)of the site]will require detailed examination to determine its significance Potentially active tectonic deformationwithin the seismogenic zone beneath a site will have to be assessed using geological geophysical andseismological methods to determine its significance Engineering solutions are generally available tomitigate the potential vibratory effects of earthquakes through design However engineering solutionscannot always be demonstrated to be adequate for mitigation of the effects of permanent grounddisplacement phenomena such as surface faulting or folding subsidence or ground collapse For thisreason it is prudent to select an alternative site when the potential exists for permanent grounddisplacement at the proposed site (Ref C4)

The level of detail for investigations should be governed by knowledge of the current and lateQuaternary tectonic regime and the geological complexity of the site and region The investigations fordetermining seismic sources should be carried out in all the following levels with areas described byradii of 320 km (200 mi) (Site Region) 40 km (25 mi) (Site Vicinity) and 8 km (5 mi) (Site Area) and 1km (06 mi) (Site Location) from the site The investigations should provide increasingly detailedinformation as they proceed from the regional level down to the site (eg from Site Region to SiteLocation) Whenever faults or other structures are encountered at a site in either outcrop or excavationsit is necessary to perform many of the investigations described below to determine whether or not theyare capable tectonic sources

C211 Site Region Investigations [within radii of 320 km (200 mi) ndash 40 km (25 mi) of the site]

The Site Region investigations should be planned to identify seismic sources and describe theQuaternary tectonic regime The data should have a resolution consistent with a map developed at ascale of 1500000 or larger The investigations are not expected to be extensive or in detail but shouldinclude a comprehensive literature review supplemented by focused geological reconnaissances based onthe results of the literature study (including topographic geologic aeromagnetic and gravity maps andairphotos) Some detailed investigations at specific locations within the region may be necessary ifpotential seismic sources that may be significant for determining the safe shutdown earthquake groundmotion (SSE) are identified

The large size of the area for the regional investigations is necessary because of the possibilitythat all significant seismic sources or alternative configurations may not have been captured orenveloped by existing PSHA source databases Thus the large area will increase the chances of (1)identifying evidence for unknown seismic sources that might extend close enough for earthquake groundmotions generated by that source to affect the site and (2) confirming the PSHArsquos database Furthermore because of the relative rarity of seismic activity in the CEUS the area should be largeenough to include as many historical and instrumentally recorded earthquakes for analysis as reasonablypossible The specified area of study is expected to be large enough to incorporate any previouslyidentified sources that could be analogous to sources that may underlie or be relatively close to the site In past licensing activities for sites in the CEUS it has often been necessary because of the absence ofdatable horizons overlying bedrock to extend investigations out many tens or hundreds of kilometers


from the site along a structure or to an outlying analogous structure to locate overlying datable strata orunconformities so that geochronological methods could be applied This procedure has also been used toestimate the age of an undatable seismic source in the Site Vicinity by relating its time of last activity tothat of a similar previously evaluated structure or a known tectonic episode the evidence of which maybe many tens or hundreds of kilometers away

It is necessary to evaluate the geological seismological and geophysical data obtained from thesite-specific investigations to demonstrate that the data are sufficient and consistent with the PSHAmethodology Specifically the evaluation may need to include (but is not limited to) seismic sourcecharacterization ground motion attenuation relationships and other PSHA-related contents (such as low-magnitude threshold and magnitude conversion relationships) If new information identified by the site-specific investigations were to result in a significant increase in the hazard estimate for a site and if thisnew information were validated by a strong technical basis the PSHA might have to be modified toincorporate the new technical information Using sensitivity studies it may also be possible to justify alower hazard estimate with an exceptionally strong technical basis However it is expected that largeuncertainties in estimating seismic hazard in the CEUS will continue to exist in the future andsubstantial delays in the licensing process will result from trying to justify a lower value with respect to aspecific site

C212 Site Vicinity Investigations [within radii of 40 km (25 mi) ndash 8 km (5 mi) of the site]

Reconnaissance-level investigations which may need to be supplemented at specific locations bymore detailed explorations such as geologic mapping geophysical surveying borings and trenchingshould be conducted for the Site Vicinity the data should have a resolution consistent with a mapdeveloped at a scale of 150000 or larger

C213 Site Area Investigations [within radii of 8 km (5 mi) ndash 1 km (06 mi) of the site]

Detailed investigations should be carried out within the Site Area and the resulting data shouldhave a resolution consistent with a map developed at a scale of 15000 or larger The level ofinvestigations should be in sufficient detail to delineate the geology and the potential for tectonicdeformation at or near the ground surface The investigations should use the methods described in thefollowing subsections that are appropriate for the tectonic regime to characterize seismic sources

The areas of investigations may be asymmetrical and may cover larger areas than those describedabove in regions of late Quaternary activity regions with high rates of historical seismic activity (felt orinstrumentally recorded data) or sites that are located near a capable tectonic source such as a fault zone


C22 Contents of Site Vicinity and Site Area Investigations

The following methods are suggested but they are not all-inclusive and investigations should notbe limited to them Some procedures will not be applicable to every site and situations will occur thatrequire investigations that are not included in the following discussion It is anticipated that newtechnologies will be available in the future that will be applicable to these investigations

C221 Surface Investigations

Surface exploration to assess the geology and geologic structure of the Site Area is dependent onthe Site Location and may be carried out with the use of any appropriate combination of the geologicalgeophysical seismological and geotechnical engineering techniques summarized in the followingparagraphs However it is not necessary for all of these methods to be carried out at a given site

C2211 Geological interpretations should be performed of aerial photographs and otherremote-sensing imagery as appropriate for the particular site conditions to assist in identifying rockoutcrops faults and other tectonic features fracture traces geologic contacts lineaments soil conditionsand evidence of landslides or soil liquefaction

C2212 Mapping topographic geomorphic and hydrologic features should be performedat scales and with contour intervals suitable for analysis and descriptions of stratigraphy (particularlyQuaternary) surface tectonic structures such as fault zones and Quaternary geomorphic features Forcoastal sites or sites located near lakes or rivers this includes topography geomorphology (particularlymapping marine and fluvial terraces) bathymetry submarine landslides geophysics (such as seismicreflection) and hydrographic surveys to the extent needed to describe the site area features

C2213 Vertical crustal movements should be evaluated using (1) geodetic landsurveying and (2) geological analyses (such as analysis of regional dissection and degradation patterns)shorelines fluvial adjustments (such as changes in stream longitudinal profiles or terraces) and otherlong-term changes (such as elevation changes across lava flows)

C2214 Analysis should be performed to determine the tectonic significance of offsetdisplaced or anomalous landforms such as displaced stream channels or changes in stream profiles or theupstream migration of knickpoints abrupt changes in fluvial deposits or terraces changes in paleo-channels across a fault or uplifted down-dropped or laterally displaced marine terraces

C2215 Analysis should be performed to determine the tectonic significance ofQuaternary sedimentary deposits within or near tectonic zones such as fault zones including (1) fault-related or fault-controlled deposits such as sag ponds graben fill deposits and colluvial wedges formedby the erosion of a fault paleo-scarp and (2) non-fault-related but offset deposits such as alluvial fansdebris cones fluvial terrace and lake shoreline deposits

C2216 Identification and analysis should be performed of deformation features causedby vibratory ground motions including seismically induced liquefaction features (sand boils explosioncraters lateral spreads settlement soil flows) mud volcanoes landslides rockfalls deformed lakedeposits or soil horizons shear zones cracks or fissures


C2217 Analysis should be performed of fault displacements including the interpretionof the morphology of topographic fault scarps associated with or produced by surface rupture Faultscarp morphology is useful in estimating the age of last displacement [in conjunction with the appropriategeochronological methods described in NUREGCR-5562 (Ref C5)] approximate magnitude of theassociated earthquake recurrence intervals slip rate and the nature of the causative fault at depth

C222 Subsurface Investigation Contents

Subsurface investigations at the site to identify and describe potential seismic sources and toobtain required geotechnical information are described in Regulatory Guide 1132 (Ref C6) Theinvestigations include but may not be confined to the following

C2221 Geophysical investigations useful in the past include magnetic and gravitysurveys seismic reflection and seismic refraction surveys bore-hole geophysics electrical surveys andground-penetrating radar surveys

C2222 Core borings to map subsurface geology and obtain samples for testing such asdetermining the properties of the subsurface soils and rocks and geochronological analysis

C2223 Excavating and logging of trenches across geological features to obtain samplesfor the geochronological analysis of those features

C2224 At some sites deep unconsolidated materialsoil bodies of water or othermaterial may obscure geologic evidence of past activity along a tectonic structure In such cases theanalysis of evidence elsewhere along the structure can be used to evaluate its characteristics in thevicinity of the site

In the CEUS it may not be possible to reasonably demonstrate the age of youngest activity on atectonic structure with adequate deterministic certainty In such cases the uncertainty should bequantified the NRC staff will accept evaluations using the methods described in NUREGCR-5503 (RefC3) A demonstrated tectonic association of such structures with geologic structural features or tectonicprocesses that are geologically old (at least pre-Quaternary) should be acceptable as an age indicator inthe absence of conflicting evidence

C23 Site Location Investigations [within 1 km (06 mi)]

Data from Site Location investigations should have a resolution consistent with a map developedat a scale of 1500 or larger Important aspects of the site investigations are the excavation and loggingof exploratory trenches and the mapping of the excavations for the plant structures particularly those thatare characterized as Seismic Category I In addition to geological geophysical and seismologicalinvestigations detailed geotechnical engineering investigations as described in Regulatory Guide 1132(Ref C6) should be conducted at the site


C24 Surface-Fault Rupture and Associated Deformation at the Site

Sites that have a potential for fault rupture at or near the ground surface and associateddeformation should be avoided Where it is determined that surface deformation need not be taken intoaccount sufficient data or detailed studies to reasonably support the determination should be presented The presence or absence of Quaternary faulting at the site needs to be evaluated to determine whetherthere is a potential hazard that is caused by surface faulting The potential for surface fault ruptureshould be characterized by evaluating (1) the location and geometry of faults relative to the site (2) thenature and amount of displacement (sense of slip cumulative slip slip per event and nature and extent ofrelated folding andor secondary faulting) and (3) the likelihood of displacement during some futureperiod of concern (recurrence interval slip rate and elapsed time since the most recent displacement) Acceptable methods and approaches for conducting these evaluations are described in NUREGCR-5503(Ref C3) acceptable geochronology dating methods are described in NUREGCR-5562 (Ref C5)

For assessing the potential for fault displacement the details of the spatial pattern of the faultzone (eg the complexity of fault traces branches and en echelon patterns) may be important as theymay define the particular locations where fault displacement may be expected in the future The amountof slip that might be expected to occur can be evaluated directly based on paleoseismic investigations orit can be estimated indirectly based on the magnitude of the earthquake that the fault can generate

Both non-tectonic and tectonic deformation can pose a substantial hazard to a nuclear powerplant but there are likely to be differences in the approaches used to resolve the issues raised by the twotypes of phenomena Therefore non-tectonic deformation should be distinguished from tectonicdeformation at a site In past nuclear power plant licensing activities surface displacements caused byphenomena other than tectonic phenomena have been confused with tectonically induced faulting Non-tectonic structures are those found in karst terrain and those resulting from growth faulting The natureof faults related to collapse features can usually be defined through geotechnical investigations and caneither be avoided or if feasible adequate engineering fixes can be provided

Glacially induced faults generally do not represent a deep-seated seismic or fault displacementhazard because the conditions that created them are no longer present However residual stresses fromPleistocene glaciation may still be present in glaciated regions although they are of less concern thanactive tectonically induced stresses These features should be investigated with respect to theirrelationship to current in situ stresses

Large naturally occurring growth faults as those found in the coastal plain of Texas andLouisiana can pose a surface displacement hazard even though offset most likely occurs at a much lessrapid rate than that of tectonic faults They are not regarded as having the capacity to generate damagingvibratory ground motion can often be identified and avoided in siting and their displacements can bemonitored Some growth faults and antithetic faults related to growth faults and fault zones should beinvestigated in regions where growth faults are known to be present Local human-induced growthfaulting can be monitored and controlled or avoided

If questionable features cannot be demonstrated to be of non-tectonic origin they should betreated as tectonic deformation


C25 Site Geotechnical Investigations and Evaluations

C251 Geotechnical Investigations

The geotechnical investigations should include but not necessarily be limited to (1) defining sitesoil and near-surface geologic strata properties as may be required for hazard evaluations engineeringanalyses and seismic design (2) evaluating the effects of local soil and site geologic strata on groundmotion at the ground surface (3) evaluating dynamic properties of the near-surface soils and geologicstrata (4) conducting soil-structure interaction analyses and (5) assessing the potential for soil failure ordeformation induced by ground shaking (liquefaction differential compaction and land sliding)

Subsurface conditions should be investigated by means of borings soundings well logsexploratory excavations sampling geophysical methods (eg cross-hole down-hole and geophysicallogging) that adequately assess soil and ground-water conditions and other methods described inRegulatory Guide 1132 (Ref C6) Appropriate investigations should be made to determine thecontribution of the subsurface soils and rocks to the loads imposed on the structures

A laboratory testing program should be carried out to identify and classify the subsurface soilsand rocks and to determine their physical and engineering properties Laboratory investigations andtesting practices acceptable to the NRC staff are described in Regulatory Guide 1138 (Ref C7) Laboratory tests for both static and dynamic properties (eg shear modulus damping liquefactionresistance etc) are generally required The dynamic property tests should include cyclic triaxial testscyclic simple shear tests cyclic torsional shear tests and resonant column tests as appropriate Bothstatic and dynamic tests should be conducted as recommended in American Society for Testing andMaterials (ASTM) standards or test procedures acceptable to the staff The ASTM specificationnumbers for static and dynamic laboratory tests can be found in the annual books of ASTM StandardsVolume 0408 Sufficient laboratory test data should be obtained to allow for reasonable assessments ofmean values of soil properties and their potential variability

C252 Ground Failure Evaluations

Liquefaction is a soil behavior phenomenon in which cohesionless soils (sand silt or gravel)under saturated conditions lose a substantial part or all of their strength because of high pore waterpressures generated in the soils by strong ground motions induced by earthquakes Potential effects ofliquefaction include reduction in foundation bearing capacity settlements land sliding and lateralmovements flotation of lightweight structures (such as tanks) embedded in the liquefied soil andincreased lateral pressures on walls retaining liquefied soil Guidance in Regulatory Guide 1198ldquoProcedures and Criteria for Assessing Seismic Soil Liquefaction at Nuclear Power Plant Sitesrdquo (RefC8) should be used for evaluating the site for liquefaction potential

Investigations of liquefaction potential typically involve both geological and geotechnicalengineering assessments The parameters controlling liquefaction phenomena are (1) the lithology of thesoil at the site (2) the ground water conditions (3) the behavior of the soil under dynamic loadings and(4) the potential severity of the vibratory ground motion

In addition to liquefaction a number of other forms of ground failure or ground settlementshould be investigated These forms of ground failure and ground settlement include localized softzones karst features seismic settlement of non-saturated soils all forms of mass wasting and any otherform of ground deformation that has the capacity to impact foundation performance or design


C3 Evaluation of New Information Obtained from the Site-specific Investigations

The first step in reviewing the new information obtained from the site-specific investigationswith previous interpretations is determining whether the following existing parameters are consistentwith the new information (1) the range of seismogenic sources as interpreted by the seismicity expertsor teams involved in the study (2) the range of seismicity rates for the region around the site asinterpreted by the seismicity experts or teams involved in the studies (3) the range of maximummagnitudes determined by the seismicity experts or teams and (4) attenuation relations The newinformation is considered not significant and no further evaluation is needed if it is consistent with theassumptions used in the PSHA no additional alternative seismic sources or seismic parameters areneeded or it supports maintaining the site mean seismic hazard

APPENDIX C REFERENCES

C1 Electric Power Research Institute ldquoThe Earthquakes of Stable Continental Regionsrdquo Volume 1 Assessment of Large Earthquake Potential EPRI TR-102261-V1 1994

C2 Budnitz RJ et al ldquoRecommendations for Probabilistic Seismic Hazard Analysis Guidance onUncertainty and Use of Expertsrdquo NUREGCR-6372 Volumes 1 and 2 US Nuclear RegulatoryCommission Washington DC April 1997

C3 Hanson KL et al ldquoTechniques for Identifying Faults and Determining Their OriginsrdquoNUREGCR-5503 US Nuclear Regulatory Commission Washington DC 1999

C4 International Atomic Energy Agency (IAEA) ldquoEarthquakes and Associated Topics in Relation toNuclear Power Plant Sitingrdquo Safety Series No 50-SG-S1 Revision 1 1991

C5 Sowers JM et al ldquoDating and Earthquakes Review of Quaternary Geochronology and ItsApplication to Paleoseismologyrdquo NUREGCR-5562 US Nuclear Regulatory CommissionWashington DC 1998

C6 Regulatory Guide 1132 ldquoSite Investigations for Foundations of Nuclear Power Plantsrdquo USNuclear Regulatory Commission Washington DC

C7 Regulatory Guide 1138 ldquoLaboratory Investigations of Soils and Rocks for Engineering Analysisand Design of Nuclear Power Plantsrdquo US Nuclear Regulatory Commission Washington DC

C8 Regulatory Guide 1198 ldquoProcedures and Criteria for Assessing Seismic Soil Liquefaction atNuclear Power Plant Sitesrdquo US Nuclear Regulatory Commission Washington DC

Appendix D to RG 1208 Page D-1

APPENDIX D

DEVELOPMENT OF SEISMIC HAZARD INFORMATION BASE ANDDETERMINATION OF CONTROLLING EARTHQUAKES

D1 Introduction

This appendix discusses site-specific development of seismic hazard levels and elaborates onmethods to meet the goals discussed in Regulatory Position 3 of this regulatory guide This appendixdescribes a methods for undertaking probabilistic seismic hazard analysis (PSHA) performingdeaggregation of the results of the PSHA and determining the controlling earthquakes that are developedfor comparison with identified local and regional seismic sources The controlling earthquakes can alsobe used to develop appropriate ground motions for the site response analysis The deaggregation of themean probabilistic seismic hazard analysis (PSHA) results determines the contribution of individualmagnitude and distance ranges to the overall seismic hazard Information from the deaggregation isuseful to both review the PSHA and understand the seismic sources that contribute most to hazard at thesite

The controlling earthquakes are developed from the deaggregation of the PSHA results at groundmotion levels corresponding to the annual frequencies of 1 E-04 1 E-05 and 1 E-06 and are based on themagnitude and distance values that contribute most the to hazard at the average of 1 and 25 Hz and theaverage of 5 and 10 Hz While the ASCESEI Standard 43-05 (Ref D2) approach only requirescalculation of ground motion levels with mean annual probabilities of 1 E-04 and 1 E-05 NRCconfirmatory activities also specify calculation of ground motion levels with a mean annual probability of1 E-06 Using the controlling earthquakes Regulatory Position 4 and Appendix E to this regulatoryguide describe one acceptable procedure for determining the appropriate ground motion for the siteresponse analysis to determine the performance-based safe shutdown earthquake ground motion (SSE)

D2 Probabilistic Seismic Hazard Assessment

Site-specific PSHA should be performed using the methodology described in RegulatoryPositions 33 and 34 of this regulatory guide Steps taken relative to the PSHA methodology aresummarized as follows

bull Perform the PSHA for actual or assumed rock conditions with up-to-date interpretations ofearthquake sources earthquake recurrence and strong ground motion estimation using originalor updated sources as determined in Regulatory Positions 31 and 32

bull CAV filtering can be used in place of a lower-bound magnitude cutoff (Ref D1)

bull Conduct the hazard assessment at a minimum of 30 frequencies approximately equally spacedon a logarithmic frequency axis between 100 and 01Hz

bull Report fractile hazard curves at the following fractile levels (p) for each ground motionparameter 005 016 050 084 and 095 as well as the mean Report the fractile hazardcurves in tabular as well as graphical format

bull Determine the mean uniform hazard response spectra (UHRS) for annual exceedance frequenciesof 1 E-04 1 E-05 and 1 E-06

The recommended magnitude and distance bins and procedure used to establish controlling earthquakes were1

developed for application in the CEUS where the nearby earthquakes generally control the response in the 5 to 10 Hzfrequency range and larger but distant events can control the lower frequency range For other situations alternativebinning schemes as well as a study of contributions from various bins are necessary to identify controlling earthquakesconsistent with the distribution of the seismicity


D3 Deaggregation of PSHA Results

Deaggregation is undertaken as a way to better understand the earthquakes that contribute most to hazardat the site of interest It is also used to assess the reasonableness of the PSHA results and is further usedto develop controlling earthquakes as described in the section below Deaggregation can be performedusing the following steps

Deaggregation Step 1

(a) Using the annual probability levels of 1 E-04 1 E-05 and 1 E-06 determine the ground motionlevels for the spectral accelerations at 1 25 5 and 10 Hz from the total mean hazard obtained inStep 1

(b) Calculate the linear average of the ground motion level for the 1 and 25 Hz and the 5 and 10 Hzspectral acceleration pairs


Perform a deaggregation of the PSHA for each of the spectral accelerations and annualprobability levels as enumerated in Step 1 and provide a table (such as illustrated in Table D1 ) for each1

of the 12 cases The deaggregation is performed to obtain the relative contribution to the hazard for eachof the magnitude-distance bins for each case

Table D1Recommended Magnitude and Distance Bins

Moment Magnitude Range of Bins

Distance

Range of Bin

(km)

5 ndash 55 55 ndash 6 6 ndash 65 65 ndash 7 gt7

0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300



If the deaggregated results for each of the 12 cases is not in terms of the fractional contribution tothe total hazard then perform the steps as described below Otherwise average the low-frequency (1 and25 Hz) and high-frequency (5 and 10 Hz) deaggregation results

From the deaggregated results of Step 2 the mean annual probability of exceeding the groundmotion levels of Step 2(a) (spectral accelerations at 1 25 5 and 10 Hz) are determined for each

mdfmagnitude-distance bin These values are denoted by H

mdfUsing H values the fractional contribution of each magnitude and distance bin to the total

1hazard for the average of 1 and 25 Hz P(md) is computed according to the following

1 mdf mdfP(md) = [( 3 H ) 2 ] divide [ 3 3 ( 3 H ) 2 ] (Equation 1) f = 12 m d f = 12

where f = 1 and f = 2 represent the ground motion measure at 1 and 25 Hz respectively

The fractional contribution of each magnitude and distance bin to the total hazard for the average

2of 5 and 10 Hz P(md) is computed according to the following




D4 Procedure To Determine Controlling Earthquakes

The following approach is acceptable to the NRC staff for determining controlling earthquakeswhich are used by the staff to assess the reasonableness of the PSHA results and can be used for the siteresponse analyses This procedure is based on a deaggregation of the mean probabilistic seismic hazardin terms of earthquake magnitudes and distances When the controlling earthquakes have been obtainedthe site specific earthquake ground motion can be developed according to the simplified proceduresdescribed in Appendix E The SSE response spectrum is then determined according to the proceduresdescribed in Regulatory Position 5

Step 1 for Determining Controlling Earthquakes

Review the magnitude-distance distribution for the average of 1 and 25 Hz to determine whetherthe contribution to the hazard for distances of 100 kilometer (km) (63 mi) or greater is substantial (on theorder of 5 percent or greater)

If the contribution to the hazard for distances of 100 km (63 mi) or greater exceeds 5 percentadditional calculations are needed to determine the controlling earthquakes using the magnitude-distance

1distribution for distances greater than 100 km (63 mi) This distribution P gt 100 (md) is defined bythe following

1 1 1P gt 100 (md) = [ P(md) ] divide [ 3 3 P(md) ] (Equation 3) m d gt 100

The purpose of this calculation is to identify a distant larger event that may controllow-frequency content of a response spectrum

The distance of 100 km (63 mi) is chosen for CEUS sites However for all sites the results offull magnitude-distance distribution should be carefully examined to ensure that proper controllingearthquakes are clearly identified


Calculate the mean magnitude and distance of the controlling earthquake associated with theground motions determined in Step 1 of the deaggregation (above) for the average of 5 and 10 Hz Thefollowing relation is used to calculate the mean magnitude using results of the entire magnitude-distancebins matrix

c 2M (5 ndash 10 Hz) = 3 m 3 P(md) (Equation 4) m d

where m is the central magnitude value for each magnitude bin

The mean distance of the controlling earthquake is determined using results of the entiremagnitude-distance bins matrix

c 2Ln D (5 ndash 10 Hz) = 3 Ln(d) 3 P(md) (Equation 5) d m

where d is the centroid distance value for each distance bin



If the contribution to the hazard calculated in Step 5 for distances of 100 km (63 mi) or greaterexceeds 5 percent for the average of 1 and 25 Hz calculate the mean magnitude and distance of thecontrolling earthquakes associated with the ground motions determined in Step 2 for the average of 1 and25 Hz The following relation is used to calculate the mean magnitude using calculations based onmagnitude-distance bins greater than distances of 100 km (63 mi) as discussed in Step 1

c 1M (1 ndash 25 Hz) = 3 m 3 P gt 100 (md) (Equation 6) m d gt 100


The mean distance of the controlling earthquake is based on magnitude-distance bins greater thandistances of 100 km (63 mi) as discussed in Step 5 and determined according to the following

c 2Ln D (1 ndash 25 Hz) = 3 Ln(d) 3 P gt 100 (md) (Equation 7) d gt 100 m


When more than one earthquake magnitude-distance pair contributes significantly to the spectralaccelerations at a given frequency it may be necessary to use more than one controlling earthquake fordetermining the spectral response at the frequency


Document the high- and low-frequency controlling earthquakes for each target annual probabilityof exceedance in the tabular form illustrated in Table D2




Table D2High- and Low-Frequency Controlling Earthquakes

bHazard Magnitude (m ) Distance

Mean 1 E-04

High-Frequency (5 and 10 Hz)

Mean 1 E-04

Low-Frequency (1 and 25 Hz)

Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06


APPENDIX D BIBLIOGRAPHY

D1 Electric Power Research Institute (EPRI) and US Department of Energy (DOE) ldquoProgram onTechnology Innovation Use of Minimum CAV in Determining Effects of Small MagnitudeEarthquakes on Seismic Hazard Analysesrdquo Report 1012965 December 2005

D2 ASCESEI 43-05 ldquoSeismic Design Criteria for Structures Systems and Components in NuclearFacilitiesrdquo American Society of Civil EngineersStructural Engineering Institute 20052

D3 SobelP ldquoRevised Livermore Seismic Hazard Estimates for Sixty-Nine Nuclear Power PlantSites East of the Rocky Mountainsrdquo NUREG-1488 US Nuclear Regulatory CommissionWashington DC April 1994

D4 Savy JB et al ldquoEastern Seismic Hazard Characterization Updaterdquo UCRL-ID-115111Lawrence Livermore National Laboratory June 1993

D5 Bernreuter DL et al ldquoSeismic Hazard Characterization of 69 Nuclear Plant Sites East of theRocky Mountainsrdquo NUREGCR-5250 Volumes 1ndash8 US Nuclear Regulatory CommissionWashington DC January 1989

D6 Electric Power Research Institute (EPRI) ldquoProbabilistic Seismic Hazard Evaluations at NuclearPower Plant Sites in the Central and Eastern United Statesrdquo NP-4726 All Volumes 1989ndash1991


D7 Electric Power Research Institute (EPRI) ldquoThe Earthquakes of Stable Continental RegionsrdquoVolume 1 Assessment of Large Earthquake Potential EPRI TR-102261-V1 1994

D8 Electric Power Research Institute (EPRI) et al ldquoCEUS Ground Motion Project Final ReportrdquoReport 1009684 2004

Appendix E to RG 1208 Page E-1

APPENDIX E

SEISMIC WAVE TRANSMISSION ANALYSIS

E1 Introduction

The horizontal and vertical safe shutdown earthquake ground motion (SSE) should be

sdetermined in the free field on the ground surface For sites that have materials with V less than theassumed generic rock shear wave velocity as defined in the probabilistic seismic hazard analysis(PSHA) a site response analysis should be performed This appendix discusses the site-specificinformation needed for these analyses and elaborates on one of the acceptable site response methodsdiscussed in NUREGCR-6728 that can be used to meet the intent of Regulatory Position 4 of thisregulatory guide The method described is a simplified approach and as such some sites may requiremore detailed analyses as described in NUREGCR-6728

The input ground motion used in the analyses are specified based on the PSHA which assumesthat an outcrop or a hypothetical outcrop exists at the free-field surface If the rock layer (as defined byshear wave velocity) first occurs at depth the input ground motions are deconvolved to develop ldquowithinrdquomotions and imposed at the generic rock horizon

The purpose of the method described in this appendix is to develop the uniform hazard responsespectrum (UHRS) at the free-field ground surface The hazard curves from the PSHA are defined forgeneric rock conditions as defined by the attenuation relationships used in the PSHA In the central and

seastern united states (CEUS) rock is usually defined as that material with a shear wave velocity (V ) ofabout 28 kmsec (9200 ftsec) To properly address amplification or deamplification effects of the soilsbetween the generic rock horizon the ground surface and other interfaces in between the followingprocedure should be used

(1) Develop the site-specific soil profile

(2) Develop appropriate modified earthquake time histories to be used in site response analyses

(3) Perform a suite of site response analyses to determine mean site amplification functions for arange of frequencies

(4) Develop the UHRS at the free ground surface based on the generic rock-based PSHA and themean site amplification functions

E2 Site-Specific Soil Profile

Site and laboratory investigations and testing are performed to obtain data defining the static anddynamic engineering properties of soil and rock materials and their spatial distribution The proceduresidentified in Regulatory Guide 1132 (Ref E1) Regulatory Guide 1138 (Ref E2) and subsectionC222 of Appendix C to this regulatory guide are acceptable to the NRC staff


The seismic wave transmission characteristics (spectral amplification or deamplification) of thematerials overlying bedrock at the site should be described over a range of frequencies that include thesignificant structural frequencies The wave transmission characteristics should be developed for levelsof seismic motion ranging from those causing very small strains (ie no soil degradation) to thoseconsistent with strain levels anticipated in the SSE The following material properties should bedetermined for each stratum under the site (1) thickness (2) compressional velocity (3) shear wavevelocity (4) bulk densities (5) soil index properties and classification (6) shear modulus and dampingvariations with strain level and (7) the water table elevation and its variation throughout the site Internal friction angle cohesive strength and over-consolidation ratio for clay are also needed for non-linear analyses Site specific soil profiles should be deep enough to fully capture the amplification to thelowest structural frequency of interest and should extend to the depth at which the input ground motion isto be imposed

The strain-dependent shear modulus and damping curves are developed based on site-specifictesting results and supplemented as appropriate by published data for similar soils One source ofpublished data is the EPRI 93 curves (Ref E3) The strain-dependent shear modulus and dampingcurves incorporated into the analysis should be justified against observed data for each soil at the site When the site-specific laboratory data are developed the result should be compared to earthquakerecordings on similar soils A maximum critical damping value of 15 percent is allowed in site responseanalyses The effects of confining pressures (that reflect the depths of the soil) on these strain-dependentsoil dynamic characteristics are assessed and considered in site response analyses The variability inthese properties is accounted for in the site response analyses

Often vertically propagating shear waves are the dominant contributor to free-field groundmotions at a site In these cases a one-dimensional equivalent-linear analysis or nonlinear analysis thatassumes vertical propagation of shear waves may be appropriate However site characteristics (such as adipping bedrock surface or other impedance boundaries) regional characteristics (such as topographiceffects) and source characteristics (such as nearby dipping seismic sources) may require that analyses beable to also account for inclined waves Multi-dimensional soil models may be needed if complexgeologic and geotechnical conditions exist

E3 Site Response Analysis

Due to the non-linear nature of site response the choice of input ground motions has a significantimpact on the amplification of motion observed in the soil column One way to approach this problem isto use controlling earthquakes determined from deaggregation of the PSHA results as described inAppendix D The controlling earthquakes are developed to focus the analyses on the types of scenariosmost likely to impact the site However for some sites additional earthquake scenarios may be needed toadequately reflect the full UHRS particularly in the intermediate frequency range

The response spectra for each of the controlling earthquakes should be developed using eitherappropriate attenuation relationships or the appropriate response spectrum from NUREGCR-6728 TheCEUS spectral shapes described in NUREGCR-6728 are for both a single corner and double cornersource model These two models should be evenly weighted and accounted for in the development of theinput time histories The resulting response spectra are then scaled to match the site rock spectralaccelerations at 75 Hz (high-frequency) 175 Hz (low-frequency) and an intermediate frequency rangeas appropriate


The fundamental frequency of the site can be approximated prior to analysis using simplifiedmethods Once the spectra for the input earthquakes are determined and scaled the spectra are plottedand compared against the fundamental frequency of the soil to ensure that the spectra from at least onekey earthquake scenario has sufficient energy content at the natural frequency of the site as determinedby the full rock-based UHRS Because the non-linear behavior of the soil will decrease the fundamentalfrequency of the site this comparison should be verified upon completion of the analyses The soilresponse is typically highest at the natural period of the soil Therefore applying a suite of cases that aredeficient in this range may not adequately predict the true site specific UHRS A visual comparison ofthe spectra from the controlling earthquakes the UHRS spectra and the natural frequency of the soilcolumn should be provided

After determining the scaled response spectra from each of the input earthquakes correspondingacceleration time histories are identified and their spectra compared to the target earthquakes spectra The acceleration time histories are modified to match the target spectra The scaled time histories whichwere recorded as outcrop motions are imposed in the developed subsurface model (and are typically firstconverted to equivalent ldquowithinrdquo motions at the bedrock level) The imposed motions propagate throughthe analytical model of the site soils to determine the free-field surface ground motions (RegulatoryPosition 42) Only acceleration time histories modified from recorded earthquakes are used for thispurpose A sufficient number of time histories should be used to get reasonably consistent averageresults

As a minimum the results of the site response analysis should show the input motion (rockresponse spectra) output motion (surface response spectra) and spectral amplification function (siteground motion transfer function) at the surface It is common practice to also provide a plot showing thepeak accelerations in the soil as a function of depth In addition to developing the spectral amplificationsfunctions at the surface it is also useful to simultaneously develop the spectral amplification functionsfor the foundation level for use in development of the SSE However because the location of thefoundation is not always known at the time at which the analyses are undertaken the functions may bedetermined at several depths including the deepest depth from the Plant Parameter Envelope In additiondetermining and providing the spectral amplification functions at a variety of depths may support reviewof the results used in determining the soil UHRS and the SSE

Due to the non-linear nature of the analyses and the heterogeneity of the soil sufficientlycapturing the variability of the soil response at the site requires that at least 60 randomized shear velocityprofiles are paired with 60 sets of randomized shear modulus and damping curves (ie one shear velocityprofile with one set of modulus reduction and damping curves) The use of 60 profiles is generallyadequate to determine a reliable estimate of the standard deviation of the site response To determine theUHRS at the free-field ground surface the site amplification functions (spectral ratios) for each inputearthquake are computed The mean site amplification function is obtained for each input earthquakescenario by dividing the response spectrum from the computed surface motion by the response spectrumfrom the input hard-rock surface motion and computing the arithmetic mean of these 60 individualresponse spectral ratios


Once the site amplification functions are developed they are applied to the free-field rock-basedUHRS To determine the site-specific soil UHRS at the free-field ground surface for each of the annualexceedance frequencies (1 E-04 1 E-05 and 1 E-06) multiply the rock-based UHRS by either the high-or low-frequency site amplification function value at each frequency by the site amplification functionthat is most appropriate for that frequency The appropriate site amplification function is determined foreach frequency based on which of the input earthquakes has a spectral value that is closest to the rockUHRS at that frequency At high frequencies this will be the high-frequency spectral amplificationfunction and at low frequencies the low-frequency site amplification function By applying theappropriate (high- or low-frequency) amplification function for each frequency to the mean rock-basedUHRS the site-specific soil-based UHRS is calculated for the free ground surface Figure E1 shows acomparison of the results of each of the soil amplification functions applied to the free-field rock UHRSand the final free-field soil UHRS

As a minimum the results of the site response analysis should show the input motion (rockresponse spectra) output motion (surface response spectra) and spectral amplification functions (siteground motion transfer functions) at the surface It is common to also provide a plot showing the peakaccelerations in the soil as a function of depth In addition determining and providing the spectralamplification functions at a variety of depths supports review of the results used in determining the soil

UHRS and the SSE

Figure E1 Free-Surface Soil Uniform Hazard Response SpectraCompared to Spectra Resulting from Scaling of Mean Rock UHRS

by Low- and High-Frequency Amplification Functions


E4 Free-Field Ground Surface Uniform Hazard Response Spectra

In accordance with Regulatory Position 43 of this regulatory guide the UHRS at the free-fieldground surface is determined to form the basis of the SSE In the method detailed above the UHRS forthe site is developed by scaling the appropriate UHRS at the rock surface by the appropriate mean siteamplification function developed for either the low- and high-frequency ranges These smooth UHRSare used in Regulatory Position 5 of this regulatory guide to develop the performance-based horizontaland vertical response spectra

APPENDIX E REFERENCES

E1 Regulatory Guide 1132 ldquoSite Investigations for Foundations of Nuclear Power Plantsrdquo USNuclear Regulatory Commission Washington DC

E2 Regulatory Guide 1138 ldquoLaboratory Investigations of Soils and Rocks for Engineering Analysisand Design of Nuclear Power Plantsrdquo US Nuclear Regulatory Commission Washington DC

E3 Electric Power Research Institute (EPRI) ldquoGuidelines for Determining Design-Basis GroundMotionsrdquo EPRI TR-102293 Palo Alto California 1993

Appendix F to RG-1208 Page F-1

APPENDIX F

CRITERIA FOR DEVELOPING TIME HISTORIES

This appendix provides criteria for developing and evaluating modified ground motions used forsoil response Actual recorded earthquake ground motion or modified recorded ground motions shouldbe used for the site response analysis Synthetic motions that are not based on seed recorded timehistories should not be used

The general objective is to generate a modified recorded accelerogram that achievesapproximately a mean-based fit to the target spectrum That is the average ratio of the spectralacceleration calculated from the accelerogram to the target where the ratio is calculated frequency byfrequency is only slightly greater than one The aim is to achieve an accelerogram that does not havesignificant gaps in the Fourier amplitude spectrum but which is not biased high with respect to the target Time histories biased high with respect to a spectral target may overdrive (overestimate damping andstiffness reduction) a site soil column or structure when nonlinear effects are important Ground motionsor sets of ground motions that are generated to ldquomatchrdquo or ldquoenveloprdquo given design response spectralshapes should comply with the following six steps

(1) The time history should have a sufficiently small time increment and sufficiently long durations Time histories should have a Nyquist frequency of at least 50 Hz (eg a time increment of atmost 0010 seconds) and a total duration of 20 seconds If frequencies higher than 50 Hz are ofinterest the time increment of the record must be suitably reduced to provide a Nyquist

y t tfrequency (N = 1(2 ) ) where ) = time increment) above the maximum frequency of interest The total duration of the record can be increased by zero packing to satisfy these frequencycriteria

(2) Spectral accelerations at 5 percent damping are computed at a minimum of 100 points perfrequency decade uniformly spaced over the log frequency scale from 01 Hz to 50 Hz or theNyquist frequency If the target response spectrum is defined in the frequency range from 02 Hzto 25 Hz the comparison of the modified motion response spectrum with the target spectrum ismade at each frequency computed in this frequency range

(3) The computed 5 percent damped response spectrum of the average of all accelerograms shouldnot fall more than 10 percent below the target spectrum at any one frequency To prevent spectrain large frequency windows from falling below the target spectrum the spectra within afrequency window of no larger than plusmn 10 percent centered on the frequency should be allowed tofall below the target spectrum This corresponds to spectra at no more than nine adjacentfrequency points defined in (2) above from falling below the target spectrum

(4) The mean of the 5 percent damped response spectra should not exceed the target spectrum at anyfrequency by more than 30 percent (a factor of 13) in the frequency range between 02 Hz and25 Hz If the spectrum for the accelerogram exceeds the target spectrum by more than 30 percentat any frequency in this frequency range the power spectral density of the accelerogram needs tobe computed and shown to not have significant gaps in energy at any frequency over thefrequency range An additional check over the 02 to 25 Hz frequency range is that the meanratio (ratio of the average record value to the target value) be greater than 10

The directional correlation coefficient is a measure of the degree of linear relationship between two earthquake1

accelerograms For accelerograms X and Y the directional correlation coefficient is given by the following equation

n _ _

x y i i x yntilde = (1 n) ( 3 [ (X - x ) (Y - y) ] ) divide oacute oacute i = 1

_ _

x ywhere n is the number of discrete acceleration-time data points x and y are the mean values and oacute and oacute are thestandard deviations of X and Y respectively

Appendix F to RG 1208 Page F-2

(5) Because of the high variability in time domain characteristics of recorded earthquakes of similarmagnitudes and at similar distances strict time domain criteria are not recommended Howevermodified motions defined as described above should typically have durations (defined by the 5percent to 75 percent Arias intensity) and ratios VA and ADV (A V and D are peak ground2

acceleration ground velocity and ground displacement respectively) which are generallyconsistent with characteristic values for the magnitude and distance of the appropriate controllingevents defining the uniform hazard response spectra However in some tectonic settings thesecriteria may need to be altered to accommodate phenomena such as directivity basin effectsand hanging wall effects

(6) To be considered statistically independent the directional correlation coefficients between pairsof time histories should not exceed a value of 016 Simply shifting the starting time of a given1

accelerogram does not constitute the establishment of a different accelerogram

B DISCUSSION

RG 1208

10 CFR 10023 paragraph (d)(1) ldquoDetermination of the Safe Shutdown Earthquake GroundMotionrdquo requires that uncertainty inherent in estimates of the SSE be addressed through an appropriateanalysis such as a probabilistic seismic hazard analysis (PSHA)

In Appendix A ldquoGeneral Design Criteria for Nuclear Power Plantsrdquo to 10 CFR Part 50 GeneralDesign Criterion (GDC) 2 ldquoDesign Bases for Protection Against Natural Phenomenardquo requires in partthat nuclear power plant structures systems and components (SSCs) important to safety must bedesigned to withstand the effects of natural phenomena (such as earthquakes) without loss of capabilityto perform their safety functions Such SSCs must also be designed to accommodate the effects of andbe compatible with the environmental conditions associated with normal operation and postulatedaccidents

Appendix S to 10 CFR Part 50 specifies in part requirements for implementing GDC 2 withrespect to earthquakes Paragraph IV(a)(1)(i) of Appendix S to 10 CFR Part 50 requires that the SSEmust be characterized by free-field ground motion response spectra at the free ground surface In view ofthe limited data available on vibratory ground motions of strong earthquakes it will usually beappropriate that the design response spectra be smoothed spectra compatible with site characteristics Inaddition the horizontal motions in the free field at the foundation level of the structures consistent withthe SSE must be an appropriate response spectrum with a peak ground acceleration of at least 01g

The 10 CFR Part 50 licensing practice required applicants to acquire a construction permit (CP)and then apply for an operating license (OL) during construction Alternatively the requirements andprocedures applicable to the NRCrsquos issuance of early site permits (ESPs) and combined licenses (COLs)for nuclear power facilities are set forth in Subparts A and C of 10 CFR Part 52 ldquoLicenses Certificationsand Approvals for Nuclear Power Plantsrdquo (Ref 3) respectively

This regulatory guide has been developed to provide general guidance on methods acceptable tothe NRC staff for (1) conducting geological geophysical seismological and geotechnical investigations(2) identifying and characterizing seismic sources (3) conducting a probabilistic seismic hazardassessment (PSHA) (4) determining seismic wave transmission (soil amplification) characteristics of soiland rock sites and (5) determining a site-specific performance-based GMRS satisfying the requirementsof paragraphs (c) (d)(1) and (d)(2) of 10 CFR 10023 and leading to the establishment of an SSE tosatisfy the design requirements of Appendix S to 10 CFR Part 50 The steps necessary to develop thefinal SSE are described in Chapter 3 ldquoDesign of Structures Components Equipment and Systemsrdquo ofNUREG-0800 ldquoStandard Review Plan for the Review of Safety Analysis Reports for Nuclear PowerPlantsrdquo (Ref 4) Regulatory Position 54 of this guide provides a more detailed description of thedevelopment of the final SSE

This regulatory guide contains several appendices that address the objectives stated above Appendix A contains a list of definitions Appendix B contains a list of abbreviations and acronyms Appendix C discusses a procedure to characterize site geology seismology and geophysics Appendix Ddescribes the procedure to determine the controlling earthquakes Appendix E describes the procedurefor determining seismic wave transmission (soil amplification) characteristics of soil and rock sites Appendix F provides criteria for developing and evaluating modified ground motions used for soilresponse analyses

This regulatory guide may address information collections that are covered by the requirementsof 10 CFR Part 50 10 CFR Part 52 and 10 CFR Part 100 which the Office of Management and Budget(OMB) approved under OMB control numbers 3150-0011 3150-0151 and 3150-0093 respectively TheNRC may neither conduct nor sponsor and a person is not required to respond to an informationcollection request or requirement unless the requesting document displays a currently valid OMB controlnumber


RG 1208 Page 3

B DISCUSSION

Background











RG 1208 Page 4












RG 1208 Page 5







RG 1208 Page 6











RG 1208 Page 7









RG 1208 Page 8








RG 1208 Page 9









RG 1208 Page 10














RG 1208 Page 11












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RG 1208 Page 15












RG 1208 Page 16











RG 1208 Page 17











RG 1208 Page 18













RG 1208 Page 19





RG 1208 Page 20


|


RG 1208 Page 21

D IMPLEMENTATION











RG 1208 Page 22

REFERENCES












RG 1208 Page 23













RG 1208 Page 24










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION


RG 1208

B DISCUSSION

Background











RG 1208 Page 4












RG 1208 Page 5







RG 1208 Page 6











RG 1208 Page 7









RG 1208 Page 8








RG 1208 Page 9









RG 1208 Page 10














RG 1208 Page 11












RG 1208 Page 12











RG 1208 Page 13














RG 1208 Page 14










RG 1208 Page 15












RG 1208 Page 16











RG 1208 Page 17











RG 1208 Page 18













RG 1208 Page 19





RG 1208 Page 20


|


RG 1208 Page 21

D IMPLEMENTATION











RG 1208 Page 22

REFERENCES












RG 1208 Page 23













RG 1208 Page 24










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION





RG 1208












RG 1208 Page 5







RG 1208 Page 6











RG 1208 Page 7









RG 1208 Page 8








RG 1208 Page 9









RG 1208 Page 10














RG 1208 Page 11












RG 1208 Page 12











RG 1208 Page 13














RG 1208 Page 14










RG 1208 Page 15












RG 1208 Page 16











RG 1208 Page 17











RG 1208 Page 18













RG 1208 Page 19





RG 1208 Page 20


|


RG 1208 Page 21

D IMPLEMENTATION











RG 1208 Page 22

REFERENCES












RG 1208 Page 23













RG 1208 Page 24










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION

RG 1208







RG 1208 Page 6











RG 1208 Page 7









RG 1208 Page 8








RG 1208 Page 9









RG 1208 Page 10














RG 1208 Page 11












RG 1208 Page 12











RG 1208 Page 13














RG 1208 Page 14










RG 1208 Page 15












RG 1208 Page 16











RG 1208 Page 17











RG 1208 Page 18













RG 1208 Page 19





RG 1208 Page 20


|


RG 1208 Page 21

D IMPLEMENTATION











RG 1208 Page 22

REFERENCES












RG 1208 Page 23













RG 1208 Page 24










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION

RG 1208











RG 1208 Page 7









RG 1208 Page 8








RG 1208 Page 9









RG 1208 Page 10














RG 1208 Page 11












RG 1208 Page 12











RG 1208 Page 13














RG 1208 Page 14










RG 1208 Page 15












RG 1208 Page 16











RG 1208 Page 17











RG 1208 Page 18













RG 1208 Page 19





RG 1208 Page 20


|


RG 1208 Page 21

D IMPLEMENTATION











RG 1208 Page 22

REFERENCES












RG 1208 Page 23













RG 1208 Page 24










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION

RG 1208









RG 1208 Page 8








RG 1208 Page 9









RG 1208 Page 10














RG 1208 Page 11












RG 1208 Page 12











RG 1208 Page 13














RG 1208 Page 14










RG 1208 Page 15












RG 1208 Page 16











RG 1208 Page 17











RG 1208 Page 18













RG 1208 Page 19





RG 1208 Page 20


|


RG 1208 Page 21

D IMPLEMENTATION











RG 1208 Page 22

REFERENCES












RG 1208 Page 23













RG 1208 Page 24










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION

RG 1208








RG 1208 Page 9









RG 1208 Page 10














RG 1208 Page 11












RG 1208 Page 12











RG 1208 Page 13














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|


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D IMPLEMENTATION











RG 1208 Page 22

REFERENCES












RG 1208 Page 23













RG 1208 Page 24










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION

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RG 1208 Page 19





RG 1208 Page 20


|


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D IMPLEMENTATION











RG 1208 Page 22

REFERENCES












RG 1208 Page 23













RG 1208 Page 24










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION

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RG 1208 Page 20


|


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D IMPLEMENTATION











RG 1208 Page 22

REFERENCES












RG 1208 Page 23













RG 1208 Page 24










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION

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RG 1208 Page 20


|


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D IMPLEMENTATION











RG 1208 Page 22

REFERENCES












RG 1208 Page 23













RG 1208 Page 24










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION

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|


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D IMPLEMENTATION











RG 1208 Page 22

REFERENCES












RG 1208 Page 23













RG 1208 Page 24










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION

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|


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D IMPLEMENTATION











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REFERENCES












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RG 1208 Page 24










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION

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|


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D IMPLEMENTATION











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REFERENCES












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RG 1208 Page 24










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION

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|


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D IMPLEMENTATION











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REFERENCES












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APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION

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|


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D IMPLEMENTATION











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REFERENCES












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APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION

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|


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D IMPLEMENTATION











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REFERENCES












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APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION

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|


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D IMPLEMENTATION











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REFERENCES












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APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION

RG 1208





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|


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REFERENCES












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APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION

RG 1208


|


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D IMPLEMENTATION











RG 1208 Page 22

REFERENCES












RG 1208 Page 23













RG 1208 Page 24










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION

RG 1208

D IMPLEMENTATION











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REFERENCES












RG 1208 Page 23













RG 1208 Page 24










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION







RG 1208

REFERENCES












RG 1208 Page 23













RG 1208 Page 24










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION







RG 1208













RG 1208 Page 24










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION



RG 1208










APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION


APPENDIX A

DEFINITIONS










































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION



































APPENDIX B

ABBREVIATIONS























APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION










APPENDIX C


C1 Introduction













C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION









C21 General



































































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION






























































APPENDIX D


D1 Introduction























Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION














Distance

Range of Bin

(km)


0 ndash 15

15 ndash 25

25 ndash 50

50 ndash 100

100 ndash 200

200 ndash 300

gt300















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION















































Mean 1 E-04


Mean 1 E-04


Mean 1 E-05


Mean 1 E-05


Mean 1 E-06


Mean 1 E-06













APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION





APPENDIX E


E1 Introduction



























UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION
















UHRS and the SSE











APPENDIX F











n _ _


_ _







B DISCUSSION









APPENDIX F











n _ _


_ _







B DISCUSSION



n _ _


_ _







B DISCUSSION

REGULATORY GUIDE 1.208

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Transcript of REGULATORY GUIDE 1.208